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Making time: What research says about re-organizing school schedules

Widespread reforms that followed publication of the seminal 1983 report "A Nation at Risk" have affected almost every aspect of teaching and learning except one: The school calendar. Indeed, today’s students attend school pretty much the same way their parents did, typically for 180 six-hour days from September to May.

However, some districts and schools across the country have experimented with different ways to organize the school day and calendar to maximize the amount of time provided for instruction. This review explores those efforts by looking at the research on the effect of time on learning and how time can be structured for the most impact.

As with many education questions, the relationship between time and learning—and strategies to increase both—would benefit from more rigorous research. For example, Walberg (1998) and Aronson, Zimmerman, and Carlos (2005) note the reliance on correlational data in existing research and call for studies using experimental designs so that the impact of extending school time on student achievement outcomes can be directly measured.

Even so, enough is known now to provide guideposts for districts and schools trying to get the most out of the school day and calendar. To explore the current research, we have ordered the discussion on time and learning as follows:

  • A brief history of the school calendar
    • How long is the current school year? 
    • How long is the current school day? 
  • Breaking from tradition
    • Year-round schools
    • Block vs. period scheduling
    • Four-day school week
    • Accommodating teenagers’ sleep cycle
    • Full-day kindergarten
  • Finding more time
    • Support for struggling students
    • Teacher planning and professional development
  • Implementation  
    • Cost
    • Child care
  • Things to consider

Time and learning

Common sense suggests that the more time spent on learning, the more in fact students will learn. But does that relationship extend to time spent in school?

Several researchers have asked that very question. Two major studies synthesized the findings of a large number of smaller studies (a process that is known as a meta-analysis) and found somewhat conflicting results (Aronson et al., 2005; Walberg, 1998). Walberg analyzed 376 studies and found that 88 percent showed a positive relationship between time and learning. Among these studies, the strongest correlations were found between learning and attendance rates, learning and lengthening the school day or week, and learning and lengthening the school year.

In contrast, the Aronson et al. meta-analysis, published by WestEd, was less definitive, noting “mixed findings about the degree to which time influences student learning.” These findings suggest that it is not the extra time itself that makes a difference, it’s how that extra time is used. The authors noted a distinction among three types of time:

  • Allocated time—the total number of days and hours students are required to attend school, including both instructional time and non-instructional time (e.g., time spent at recess, lunch, making transitions, attending assemblies and other non-classroom activities).
  • Engaged time—the time when students are actually “engaged” in learning activities, which is much harder to quantify and document.
  • Academic learning time—the “precise period when an instructional activity is perfectly aligned with a student’s readiness and learning occurs.”

Their analysis shows that:

  • There is little to no relationship between allocated time and student achievement.
  • There is some relationship between engaged time and achievement.
  • There is a larger relationship between academic learning time and achievement.

Other research has pointed out the limited amount of time students spend engaged in or participating in academic activities (also referred to as “time on task”). Crawford (2004) analyzed the typical high school calendar and found that after subtracting time for holidays, professional development days, early dismissal and parent conferences, field trips, assemblies, concerts and award presentations, and state and district testing, approximately 13 to 18 six-hour days remain per subject in the typical school year.

Aronson et al. concluded: “This then—maximizing the time during which students are actively and appropriately engaged in learning—is one lens through which any education reform measure should be viewed. … Only when time is used more effectively will adding more of it begin to result in improved learning outcomes for all students.”

A brief history of the school calender

The basic public school September–June schedule emanates from the nation’s agrarian past, with a conventional school calendar of nine months followed by a three-month summer vacation during which time many children helped with harvesting crops. Another vestige of our rural past is that some schools in the South and the Midwest start up in late August, yet have a one- or two-week break in the fall at harvest time.

Although the United States is no longer a farm-based society, the nine-month on/three-month off schedule persists. "A Nation at Risk" addressed the issue of time, urging school districts and state legislatures to “strongly consider seven-hour school days, and a 200- to 220-day school year” (U.S. Department of Education, 1983). In the report’s wake, 37 states had considered proposals to extend the school year by 1990, yet very few were actually approved given the exorbitant estimated costs for such changes (Aronson et al., 2005).

Oregon provides an example of how states back-tracked after attempting to increase school time. In 1991, the legislature adopted the Education Act for the 21st Century, which was intended in part to lengthen the school year from 175 days to 220 days over the next two decades. Yet the first incremental step never happened, since the legislature repealed the act in 1995, after determining that the state could not afford the increase (Aronson et al., 2005).

Concerns about the relationship between time and learning persisted, leading to the creation and work of the National Education Commission on Time and Learning. The commission’s 1994 final report,  "Prisoners of Time," argued that the school day is “easily reduced at the secondary level to about three hours of time for core academic instruction” due to the encroachment of other requirements (e.g., education about personal safety, consumer affairs, AIDS education, conservation and energy, family life, driver’s training) and traditional nonacademic activities (e.g., counseling, gym, study halls, homeroom, lunch, pep rallies). The commission called on the nation to “reclaim” the academic day by “providing at least 5.5 hours of core academic instructional time daily.”

Beyond the tenacious hold of our agrarian past on schools’ schedules, another relic stifles the nation’s ability to address the relationship between time and learning: Public education’s reliance on a factory model with subjects broken into small, specialized units and expectations that students will move through these units at an even rate (Hawley and Darling-Hammond, 1997). "Prisoners of Time" noted that the factory model disavows the need to differentiate, leading to problems for students who need more or less time to grasp concepts. As described in the report: “[S]tudents are caught in a time trap—processed on an assembly line scheduled to the minute.” (National Education Commission on Time and Learning, 1994).

How long is the current school year?

The length of the school year is typically described either in the number of minimum days or number of minimum hours. Many states now require a minimum of 180 school days. The move to 180 days has been slow, however, with only 14 states having made this increase since 1980 (Tomlinson, 2004). Additionally, five states now require more than 180 instructional days, compared with four in 2000 and just one in 1994 (Cavell, Blank, Toye, and Williams, 2005; National Education Commission on Time and Learning, 1994).

The number of states mandating at least a 180-day school year has not changed much since 1989 (33 in 1989 and 34 plus the District of Columbia in 2004). Only five states now require less than 175 days. Michigan requires the most at 185 days (Cavell et al., 2004). (See Table 1).

Table 1
Length of School Year, State Policies in Number of Days or Total Hours, 2004
State Days Hours (Grade) Days After Exception Hours After Exception
Alabama 175  --  --  
Alaska 180  Varies  740 (K-3); 900 (4-12)  No minimum 
Arkansas  178  No minimum  Varies 
California  180  --    163 
Colorado  170  968 (1-6); 1056 (7-12)  Varies  No minimum 
Connecticut  180  900  --   
District of Columbia  180   --  --  
Delaware  -- 440 (K); 1060 (1-11; 1032 (12)     
Florida  180  --  -- 177
Georgia 180 810 (K-3); 900 (4-5); 990 (6-12)  Varies*  Varies 
Hawaii  183 --  --  
Idaho  170  450 (K); 810 (1-3); 900 (4-8); 990 (9-12)     
Illinois  185  --  Yes  176 
Indiana  180  900 (K-6); 1080 (7-12)  Varies*  Varies 
Iowa  180  990 (1-11); 962.5 (12)  Varies*  No minimum 
Kansas  186  1116  1086  181 (12) 
Kentucky  --  1050    Varies 
Louisiana  177  1062     
Maine  180  --  No minimum  175 (K-12)
Maryland  180  1080 (E, M); 1170 (H) Varies Varies
Massachusetts 180 425 (K); 900 (E); 990 (H) Varies 168 (12) 
Michigan  185  1098     
Minnesota  --  --  --   
Mississippi  180  990  Varies*  Varies 
Missouri  174  522 (K); 1044 (1-12)  Varies  Varies 
Montana  180  360 (K); 720 (1-3); 1080 (4-12)  --   
Nebraska  --  400 (K); 1032 (E); 1080 (H)  Varies*  No minimum 
Nevada  180  --  --   
New Hampshire  180  --  --   
New Jersey  180  --  --   
New Mexico  180  990 (K-6); 1080 (7-12)  --   
New York  180  --  --   
North Carolina  180  1000   --   
North Dakota  173  -- 
Ohio  182  --    Varies 
Oklahoma  180  1080  --   
Oregon  --  405 (K); 810 (1-3); 900 (4-8); 990 (9-12)  360 (K); 765 (1-3); 855 (4-8); 945 (9-12)   
Pennsylvania   180 900 (K-6); 990 (7-12)  Varies, plus longer year for charters   No minimum
Puerto Rico  170  --  --   
Rhode Island  180  --    171 (12) 
South Carolina  180  --  --   
South Dakota  170  875 (1-3); 962.5 (4-12)  --   
Tennessee  180  --  --   
Texas  180  --    172 
Utah  180  990  Varies*, plus hours for local program  172 
Vermont  175  --  --   
Virginia  180  990  Varies*  Varies 
Washington  180  450 (K); 1000 (1-12)  Varies  No minimum 
West Virginia  180  --  --   
Wisconsin  180  437 (K); 1050 (1-6); 1137 (7-12)  437 (K); 1050 (1-6); 1137 (7-12) Varies 
Wyoming  175  450 (K); 900 (E); 1050 (M); 1100 (H) --  Varies 
Total  35 states >= 180 days     19 states with policy 27 with policy 
Note: -- indicates state does not have a requirement in this category.
K = kindergarten
E = elementary
H = high school
*special circumstances apply including state emergency, disaster
Reprinted with permission from CCSSO (Council of Chief State School Officers), "Key State Education Policies on PK-12 Education: 2004."

Based on data from the National Center for Education Statistics (NCES), the number of hours per school year has also increased nationally. In 1988, the average number of hours spent per year in public school was 1,140; by 2000, this number reached 1,180. Public school students in the Midwest attend more hours (1,220) than those in the South (1,180), Northeast (1,160) and West (1,130) (National Center for Education Statistics, 2005).

How much school time do other countries deliver?

International comparisons show a lot of variation in the amount of time students are in school, but little relationship to reading scores. (See Figure 1.) Among 15-year-olds in the 22 countries participating in the 2000 Program for International Student Assessment (PISA), the U.S. level of 990 instructional (not allocated) hours per year was the fifth highest — behind Austria (1,120 hours) and France, Italy, and Japan (1,020 hours each) — while U.S. performance was near the international average. On the other hand, Finnish 15-year-olds received 858 hours of instruction per year — among the least —yet outperformed their peers worldwide (OECD, 2002).


In another international study, the 2001 Progress in International Reading Literacy Study (PIRLS), U.S. 4th graders received more instructional time, on average, than students in every country except Italy, which had the same amount—1,040 hours (National Center for Education Statistics, 2005).

The number of instructional hours offered or required varies at different schooling levels in recognition of age-appropriate content and developmental differences. While these differences in requirements are not huge, they do add up over the course of a year. For example, in Maryland, elementary and middle school students attend 1,080 hours per year, whereas high school students complete 1,170 hours per year (Cavell et al., 2005).

Another area of the school calendar that is changing is the start date—it is creeping into August. In 1988, just over half the nation’s schools opened before September 1; in 2000, three-quarters did—a 50 percent increase (Metzger, 2002). Only a few states have laws requiring schools to start on a certain date, most often leaving it to the discretion of local education agencies. Several of the states that do have mandatory start dates appear to have implemented such policies to address the concerns of the state’s tourism industry rather than education needs. (Michigan, Minnesota, and Virginia all require start dates after Labor Day.)

Despite such minor modifications from policymakers and legislators, the nine-month schedule persists.

How long is the current school day?

School days in the United States are slowly becoming longer, according to NCES data (National Center for Education Statistics, 2005). But like the nine-month school year, the six-hour school day is still close to what it’s always been—the average public school day was 6.3 hours in 1988 and rose slightly to 6.5 hours in 2000.

These hours vary slightly across school levels and across most school characteristics. Public middle school students have the highest average school day, with NCES reporting a 6.8 hour average for middle schools, compared with 6.5 hours for elementary schools and 6.6 hours for high schools.

Additionally, schools in the Midwest have the longest average days (6.9 hours for middle and high schools, and 6.7 for elementary schools), while rural schools have longer average days than central city or urban fringe schools (6.9 hours for middle schools, and 6.7 hours for elementary and high schools).

The average school day largely parallels state regulations on minimum hours per day for public school instruction. In 2004, 40 states and the District of Columbia set minimums, and 34 of those states required five or more instructional hours per day in grades one through high school. The difference in requirements is not huge—typically only about 30 minutes. For example, California requires that 1st- to 3rd-graders attend 4.7 hours; 4th- to 8th-graders attend five hours; and 9th- to 12th-graders attend six hours. As in 2002, all state high school minimums ranged from 47 hours per day in 2004, except for Missouri, which placed three hours at the lower limit, and West Virginia with a policy of 3.75 hours per day (Cavell et al., 2005). (See Table 1.)

Breaking from tradition

While the number of school days and hours remain relatively unchanged, many schools and districts have implemented strategies to use this time more efficiently. Three of these strategies are described below: Year-round schools, block schedules, and four-day school weeks.

Year-round schools

The traditional school calendar—nine months during late August or early September through late May or early June—predominates in U.S. public schools. However, some communities are changing this by adopting year-round schedules. Year-round schooling typically does not add instructional days, rather most year-round schools spread out the average 180 days of school across all 12 months.

As of 2003–2004, 7 percent of all public schools had moved to “year-round” or “modified” calendars (Strizek, Pittsonberger, Riordan, Lyter, and Orlofsky, 2006). The National Association for Year-Round Education (NAYRE) reports that the number of schools with this type of schedule has dramatically increased over the past two decades—more than 2.1 million students attended year-round public schools in 2005–2006, which is more than five times the number of students on year-round schedules in 1985 (NAYRE, 2006).

Districts and schools that have turned to year-round schedules typically do so for one of two reasons: To combat summer learning loss or to address overcrowding (NAYRE, 2006). Research shows that students’ test scores, in general, fall over summer vacation, and that low-income students experience the greatest declines, especially in reading (Cooper, Nye, Charlton, Lindsay, and Greathouse, 1996). NAYRE estimates that more than half of year-round schools have adopted this calendar in order to maintain learning throughout the summer months and prevent academic backsliding (NAYRE, 1998).

Using modified calendars is also a popular strategy for addressing overcrowding—about 41 percent of year-round schools create multiple tracks with staggered attendance for different groups of students, according to NAYRE (1998). A multi-track, year-round school divides the entire student body and staff into three, four or five different tracks. For example, in a four-track system, at any one time, three of the four tracks attend school while the fourth track is on vacation. When the fourth track of students returns from vacation, another track leaves. Thus, the student population rotates in and out of school, one track replacing another on vacation, which allows the enrollment of the school to exceed its capacity.

The preponderance of multi-tracking in year-round schools is evidenced by the fact that the average year-round school is larger than the national average for public schools on a “traditional” schedule. The average year-round elementary school has 695 students, compared with 476 students nationally; similarly, at the high school level, the average year-round school has 977 students, compared with 722 students nationally (NAYRE, 2006).

Where are year-round schools found?

Year-round schools are definitely concentrated in certain segments of public education:

  • The elementary school level accounts for the bulk of public schools using this calendar—with the 2,237 elementary schools representing 73 percent of all year-round enrollment (1,553,882 students).
  • Charter schools are more likely to use this type of calendar, with 12 percent operating a year-round schedule (Strizek et al., 2006). NAYRE data show that 46,548 of year-round students are in 123 charter schools (NAYRE, 2006).
  • NCES also found central city schools are more likely than urban fringe and large town schools or rural schools to operate year-round, (eight percent compared with five percent and four percent).
  • More than half of all year-round schools are in California (1,447 of 2,850 schools).

NAYRE reports that 46 states now have one or more year-round schools. Despite their increase, only 17 states have developed a policy regarding year-round schools (Cavell et al., 2005).

Some states have entered into the year-round arena by offering special funding programs targeted at increasing instructional time for students who are academically at risk. Texas and California have funding programs that allow districts to provide extended learning opportunities. California’s program is specifically targeted toward districts that are planning and implementing multi-track, year-round schools in an effort to address overcrowding or reduce class sizes. In Texas, the Optional Extended Year Program is targeted at districts with high percentages of K-8 students who are at risk of academic failure. Districts apply to the program, with eligibility based on percentage of students who are economically disadvantaged as defined by the Texas Education Agency. An optional extended-year program may extend the day, the week, or the year. The program must be conducted beyond the required instructional days and may include intersessions for year-round programs (Brown, 2000). For example, in 2001–2002 the Austin school district received $1.2 million to offer extended day, extended week, year-round schools March intersession, and summer school to 2,609 students. The efforts were deemed a success—95 percent of the participating students were promoted that year Washington, 2002).

When considering a modified or year-round schedule, there are numerous calendar options. Palmer and Bennis (1998) describe three of the most common schedules:

  • 60–20 and 60–15: The year is divided into three 60-day sessions with three 20-day vacation periods. A variation on this schedule is the 60–15, which allows for an additional three–four week common vacation. As with most year-round schedules, this plan can be carried out using either a single-track or multi-track system. Together, these two types of calendars account for 37 percent of all year-round schools.
  • 45–15 and 45–10: These schedules account for the largest portion of all year-round calendars (40 percent). In the 45–10 system, 45 days of instruction are followed by 15 days of vacation. The related 45–10 plan provides an additional four-week common vacation for staff and students. Again, either of these plans can be implemented in either a single-track or multi-track system.
  • Concept 6: The year is divided into six terms of approximately 43 days. This plan is typically used as a three-track, year-round schedule to address overcrowding issues with students and teachers divided into three groups that attend two consecutive sessions and then have one session off. This pattern is repeated for a total of 172 instructional days. During the 1997–1998 school year, eight percent of year-round schools were following this plan. (See Table 2.)
Table 2
Year-Round School Year Calendars Compared with Traditional Calendar
Calendar Number of Hours Per Month
 Sept Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Total
 Traditional 20 20 20  20  20  20  20  20  20  180 
 45 - 15 20  20  20  20  20  20  20  20  180 
 60 - 20 20 20 20 0 20 20 20 0 20 20 20 0 180
Concept 6 20 20 20 20  0 9 20 20  20 17  172

Are year-round schools effective?

The answer seems to be a qualified “yes.”

Although much of the research on year-round schools is based on small samples, a few meta-analyses indicate a positive relationship between a year-round schedule and academic achievement. Palmer and Bennis (1998) analyzed 33 studies on year-round education and found “significant positive effects” in 27 of them, or 75 percent. Studies included specifically examined effects on reading and math—11 of 13 comparisons in reading and 9 of 11 in math showed significant positive results.

A few limitations to the research were noted by Palmer and Bennis, however. For example, almost three-quarters of the studies were focused on the elementary level, so less is known about achievement results at the secondary level. In addition, the studies did not always specify the type of year-round calendar or whether it allowed for additional days of instruction through intersessions (the break between the regular academic sessions) or other extended learning programs. Palmer and Bennis also determined that the few studies attempting to examine the effects of intersessions suffered from poor research design.

Nonetheless, they wrote: “In sum, it is reasonable to conclude that students attending [year-round schools] are likely to perform as well as if not better than their peers in traditional nine-month programs.”

Cooper et al. (1996) and Kneese (1996) found similar though less affirmative results regarding year-round education’s impact on achievement. Kneese’s review says that year-round schools provided “effective maintenance and improvement of the overall academic performance of students participating in a year-round education program in comparison to those on the traditional calendar.”

Cooper et al. (1996) noted other non-academic benefits to year-round schools. For example, they found that parents and staff who participated in modified calendar programs were quite positive about their experiences. Palmer and Bennis (1998) were less clear, however, finding mixed results in the studies that investigated the interaction of year-round schooling and student attendance rates, teacher absenteeism, teacher attitudes, and teacher professional development.

Charter Schools and Schedules

Charter schools appear to be at the forefront of scheduling reforms, with more of these schools searching for ways to extend learning time through year-round calendars and the use of block scheduling.

While 7 percent of all public schools operate on a year-round schedule, 12 percent of charter schools do, and almost half use block schedules, compared with one-third of traditional public schools (Strizek et al., 2006). In Massachusetts, 82 percent of the 48 charter schools in operation during the 2003-04 school year maintained a school week longer than the traditional 32.5 hours (Farbman and Kaplan, 2005). About 50 percent maintained a school calendar longer than the typical 180 days.

Block vs. period scheduling

As education officials and policymakers seek ways to increase “time on task” for public school students, one of the strategies they have considered is the use of block schedules—schedules that offer classes in longer “blocks” of time (usually 90-minutes or more) with subjects offered on alternating days or alternating semesters or trimesters (a school year divided into three semesters). This is not a new concept—during the 1960s and 1970s, as many as 15 percent of junior and senior high schools experimented with some form of “flexible modular scheduling,” yet this strategy was eventually abandoned by most (O’Neil, 1995).

Block scheduling has definitely caught on in certain states. For example, in 1992–1993, only 2 percent of North Carolina used a 4 x 4 block schedule, yet by 1996–1997, 65 percent of the state’s high schools did (North Carolina Department of Public Instruction, 1997). Similarly, only five Virginia high schools used some form of block schedules in 1991–1992, but by 1995–1996, almost half (133 or 46 percent) of the state’s 290 high schools did (O’Neil, 1995).

Types of block schedules

The Northeast and Islands Regional Educational Laboratory (1998) describe some of the more popular block schedules, along with their advantages and disadvantages:

The trimester plan: The school year is organized into three sessions (trimesters), with students attending two core classes per trimester. These core classes can be coupled with up to three other year-long elective classes. Students complete the core classes in 60 days and then move on to another two core classes.

Trimester plan advantages:

  • Students concentrate on only two core courses per trimester.
  • Students and teachers prepare for fewer courses each trimester.
  • Teachers work with fewer students during each trimester.

Trimester plan disadvantages:

  • Students may not retain knowledge of fall courses when taking state and other standardized tests in the spring.

The 4x4 block: The school day is divided into four blocks, with classes lasting anywhere from 85 to 100 minutes with additional time for lunch and transitions. Students complete in one semester what would have taken them a full year in traditional schedules.

4x4 block advantages:

  • Students and teachers receive increased instructional time.
  • Students concentrate on only four courses per semester.
  • Teachers work with fewer students during the semester because they typically teach fewer classes during the semester.
  • Students and teachers prepare for fewer courses each semester.

4x4 block disadvantages:

  • Students may not retain knowledge of fall courses when taking state and other standardized tests in the spring.

The alternating plan (also known as the 8-block plan or the A/B plan): Using this format, students attend eight blocks of classes (again, typically 90 minutes long) over two days.

Alternating plan advantages:

  • Students and teachers receive increased instructional time.
  • Students have fewer classes, quizzes, and homework assignments each day.

Alternating plan disadvantages:

  • Teachers still have a large number of students, just spread over two days.
  • Both teachers and students have as many classes for which to prepare.

The 75-75-30 plan: This scheduling plan is one in which students take three classes each for two 75-day terms, followed by a 30-day intensive course or enrichment program. Variations include placing the 30 days between the two 75- day terms, having three long classes and one short class, or changing the configuration to 75-15-75-15.

75-75-30 plan advantages:

  • Students who need more time and instruction can get it during the short term.
  • Students are able to engage in a short-term enrichment program of interest to them.
  • Time is available to make up incomplete work.

75-75-30 plan disadvantages:

  • Students may not retain knowledge of fall courses when taking state and other standardized tests in the spring.

While there are no national estimates of how widely each of the above schedules is used, the Indiana and Illinois data analyzed by Harmston et al. (2003) indicates that the A/B schedule was the most popular in those states, accounting for a full five out of every six block-scheduled schools. The 4X4 schedule was second.

Benefits of block scheduling

Proponents of block schedules point to the following benefits:

More time on task: With longer class periods, classroom learning is less rushed; less time is spent on transitions between classes and classroom management activities, such as calling attendance and organizing and focusing the class. Teachers have the flexibility that enables them to allow students to spend more “time on task,” practicing and working with particular information and ideas (Northeast, 1998).

Depth and breadth: With more time, teachers can delve more deeply into subject matter, because they are no longer pressed by the clock to squeeze as much content as possible into a single lesson. The longer periods allow students the opportunity to experience subject material through a mixture of learning contexts and media. Math and science teachers especially appreciate the added time to conduct more in-depth exercises and lab experiments (Northeast, 1998).

More opportunities for planning and professional development: The longer blocks of time enable schools to build in reserve time for teachers to engage in common planning and on-site professional development.

Stronger adult-child relationships: More time allows for greater interaction between teacher and student; when teachers have fewer students in class and students have fewer teachers, more in-depth relationships can be forged. Farbman and Kaplan (2005) found that teachers report satisfaction with the teaching load from this arrangement (typically three–four classes and a total of approximately 70–80 students compared with five–six classes and about 100 students in a traditional schedule), saying it allowed teachers to track their students’ progress, and made the job much less overwhelming.

In addition, studies indicate that discipline problems decrease (O’Neil, 1995; Freeman, 2001). As one high school teacher explained, “It’s a whole lot easier managing 75 kids,” as opposed to 125 under the traditional period (O’Neil, 1995).

While block scheduling has re-emerged over the past two decades, the traditional “period” schedule (where students typically take six to eight subjects a day, in 45– to 50-minute blocks of time) persists, with almost two-thirds of public schools on a traditional schedule in 2004 (Strizek et al., 2006). Yet block scheduling is more prevalent in certain types of schools:

  • High schools were more likely to use this strategy (45 percent vs. 32 percent of elementary schools).
  • Charter schools were more likely to use block scheduling than non-charter public schools (49 percent vs. 34 percent).
  • Public schools were more likely than private schools to adopt block schedules (35 percent vs. 24 percent).
  • Central city schools were more likely to use block schedules (43 percent) than urban fringe schools (33 percent) or rural schools (29 percent).

Effectiveness of block scheduling

Research on block schedules has shown mixed results in terms of impact on academic achievement, with the 4X4 block schedule appearing to produce the least gains.

A few studies have compared results between blocked and non-blocked schools on college admissions or AP scores. ACT researchers Harmston, Pilska, Ziomek, and Hackman (2003) analyzed longitudinal differences in ACT scores for Illinois and Indiana high schools on traditional and block schedules. Over a period of seven years, the study found that:

  • The mean ACT score in all subjects increased for those on a traditional eight-period schedule.
  • The mean ACT scores for students in eight-block (or A/B block schedule) schools varied from year to year, with a slight increase after implementation.
  • The mean ACT scores for students in 4X4 block schools declined in the years immediately following implementation, but scores bounced back somewhat in the fourth year after implementation, except in reading.

Similarly, The College Board (1998), examined AP scores for calculus, biology, U.S. history, and English literature comparing students on an extended plan (60-minutes plus), traditional period, and 4X4 schedule. The analysis found that those on the 4X4 schedule scored the lowest, while those in extended classes scored the highest.

Nonetheless, the research literature includes reports from individual schools with positive outcomes due to the introduction of the 4X4 schedule.

  • Daily attendance, the percentage of pupils making the honor roll or going on to four-year colleges, and the number of course credits earned by students are all higher since Wasson High School in Colorado Springs adopted its new schedule in 1990. The failure rate is lower (O’Neil, 1995).
  • In an unusual set-up, South Springfield High School in Indiana adopted a 4X4 block schedule in 1994, but the school also allowed students to choose among 4X4, traditional, or some block and some traditional classes. Veal and Schreiber (1999) found no significant differences among students in the three groups in state-administered test scores of reading, language arts, and mathematics.

Interestingly, most block schedules result in the loss of allocated instructional time. For example, in a traditional schedule, a student would have 165 hours in any one subject (180 days times 55 minute period), while in most block schedules, a student receives only 135 hours (90 days times 90 minute period). But less time is lost to administrative tasks such as taking attendance and transitions into and out of the classroom. The loss of allocated time can be overcome by increasing the amount of engaged time if teachers reduce their use of lecture and turn to new strategies such as cooperative and small group learning, hands on projects or labs, and increased use of technology (Freeman, 2001).

Key to the successful implementation of block scheduling is appropriate professional development to help teachers move away from reliance on lecture (Irmsher, 1996). Teachers who are most effective in block scheduling often plan lessons in three parts: Explanation, application, and synthesis. Teachers generally have much less experience with the latter two phases. Teachers may also need training in cooperative learning, class building, and team formation.

Four-day school week

Rural Kentucky District Posts Gains with Four-Day School Week Schedule

Webster County, a small rural school district in Kentucky, adopted a four-day school week in 2003–2004 after an intensive planning process found that most absences for students and staff occurred on Mondays and Fridays, and holidays most often fell on Mondays. District officials reviewed other districts with four-day school weeks and ultimately adopted a Tuesday–Friday schedule. Because Kentucky defines the school calendar in hours instead of days, the district was free to organize its time into 163 student instructional days as opposed to the traditional 175-day model (students attend school for 1,050 instructional hours per year, and attend a minimum of six instructional hours per day).

The district documented the following changes in just two years:

  • Increased scores on all areas of the Comprehensive Test of Basic Skills for two consecutive years.
  • Increased scores on the state assessment for two consecutive years.
  • Decreased suspensions and code-of-conduct violations.
  • Improved response to behavior management strategies for special education students with behavioral issues.
  • Increased collaboration and planning among teachers, which in turn improved academic rigor and lesson preparation.
  • More core content covered during the school year.

Source: Yarbrough and Gilman, 2006

A scheduling strategy that has been adopted by some rural school districts is to drop the fifth day of instruction by adding time to the remaining four weekdays (Yarbrough and Gilman, 2006). A few hundred districts in Arizona, Arkansas, California, Colorado, Kansas, Louisiana, New Mexico, Oregon, South Dakota, Wisconsin, and Wyoming have implemented this schedule, primarily for fiscal reasons (cutting down on transportation costs). An unforeseen bonus is that the schedule has unexpected educational and morale benefits for both students and staff.

In Colorado, 52 of the state’s 178 districts have adopted the four-day model. Most of the districts using this calendar were small, serving only one percent of Colorado’s public school students. The Colorado Department of Education found that students, parents, and teachers overwhelmingly favored the shorter week (Dam, 2004). The Colorado study concluded that the effects on student achievement were not as substantial as the financial gain—transportation and food service costs were reduced by 20 percent—with test scores showing that students do “no worse” than those on the traditional five-day schedule (Dam, 2004).

The four-day school week works best in states that allow the option of counting hours and days when meeting the minimum school requirements. Arkansas, Illinois, Minnesota, and Virginia have legislative provisions that specifically allow for this schedule.

Accommodating teenagers’ sleep cycle

Some districts are adjusting high school start times in light of research suggesting that the sleep-wake cycle shifts during adolescence leads to teenagers’ natural tendency to fall asleep later and wake up later (Graham, 2000). A recent study from Northwestern University builds on this research, finding that high school students performed better later in the day than early in the morning, and most high school schedules contribute to sleep deprivation among students (Tonn, 2006).

Back in 1997–1998, the 39,000-student Minneapolis school system switched its high school start time from 7:15 a.m.–8:40 a.m., and dismissed students later in the day. The results? Improved attendance, less sleeping in class, and less student-reported depression, according to a study analyzing five years of data on the system’s 12,000 high school students (Wahlstrom, 2002).

In 2005, the Tulsa, Oklahoma school district also switched school start times for its 41,000 public school students. High schools now start at 8:45 a.m., instead of 8:00 a.m. To accommodate the change, elementary schools are opened later, from 8:00 a.m.–2:45 pm. The elementary school principals hoped the change would help address concerns about young students who were being dropped off at school by working parents before the school staff arrived.

Late-Start High Schools at Low Cost

By involving the public and a consultant, the Arlington (Va.) Public Schools found a way to open high schools later without disrupting the budget or other school schedules. Read this school district story.

The suburban Edina, Minneapolis, school district implemented a later high school start time and found that a greater number of students were more alert during the first two school periods than they had been during the earlier start time. Slightly more than half of the teachers reported seeing fewer students sleeping at their desks (Graham, 2000).

The school board in West Des Moines, Iowa changed the high school start time from 7:45 a.m. to 8:20 a.m. for the 2005–2006 school year. The altered schedule will lead to more efficient use of buses, saving the system $700,000 annually. “The sleep research was the catalyst, and the money was the motivation,” said Kay Rosene, the director of school and community relations for the 8,700 student district. “Without the need to cut the budget, we might not have had any change.” (Tonn, 2006).

Full-day kindergarten

Half-day kindergartens are still the norm. Only 12 states require that students attend kindergarten, although most states (41 and the District of Columbia) require that public schools offer a kindergarten program. State policies regarding kindergarten have not changed much in the past decade, with nine states requiring full-day programs (compared with 10 in 1995), 23 states requiring half-day programs, and 12 requiring either of the two (Cavell et al., 2005). Only nine states report no policy on the matter.

Kindergarten attendance, especially in full-day programs can provide great benefits to many students, according to the National Early Childhood Longitudinal Study. This study, conducted by NCES found that children in full-day kindergarten classes learned more during the year in both reading and mathematics compared to those in half-day classes, after adjusting for learning differences associated with race and ethnicity, poverty status, fall achievement level, sex, class size, relative amount of time for subject area instruction, and the presence of an instructional aide (Walston and West, 2004) . (See Figure 2.)


Finding more time

Increasing time in school or reorganizing schedules in alternative formats may not lead to the desired gains in academic achievement, researchers note. “In cases where time is not already well used, increasing allocated time is not likely to produce substantial gains in student achievement,” say Aronson et al. (2005). “In such cases, the first step should be to improve the quality of existing time,” they suggested.

For this reason, this brief is also interested in how these strategies can help make sure time is well used:

  • How do scheduling strategies provide support for struggling students?
  • How do alternative schedules enhance teacher planning time and opportunities for professional development?

Support for struggling students

Intersessions in year-round schools and block schedules are seen as two methods to support students who are struggling. Although there is little empirical data supporting the use of intersessions to improve academic achievement for at-risk students, most year-round programs target students through such initiatives based on the summer learning loss research (Cooper et al., 1996).

A recent study by Massachusetts 2020 investigated how schools extend learning time and identified eight schools that use different strategies for adding instructional time to the day and year. At Boston’s Roxbury Preparatory Charter School students attend classes for eight hours each day and have double the instructional time for math and language arts (Farbman and Kaplan, 2005). As a result, the percentage of students passing the MCAS (the state’s standardized test) increased dramatically. Only 70 percent of the students in the class of 2002 (who did not have double math classes until their eighth grade year) passed the eighth grade math MCAS, yet 100 percent of those in the class of 2004 (who had three years of double math) passed the MCAS.

Longer classes enabled through block scheduling allow teachers to provide better differentiation (O’Neil, 1995; Farbman and Kaplan, 2005). Farbman and Kaplan note that teachers in the target schools were able to divide the class into groups, with each group working on different activities based on its specific needs. Although teachers worked between six and 18 extra hours per week, not all of the additional time was spent in the classroom; “generally [teachers] spend much of the extra time tutoring students, supervising enrichment activities, participating in professional development, and planning their own classes.”

Teacher planning and professional development

Schools can take advantage of the longer blocks of “free time” available to teachers under block schedules for professional development and teacher planning time.  An example of how schools can build in professional development time by modifying schedules comes from Webster County, Kentucky, where the district implemented a four-day school week.  The school district credits the success of this approach (see box) to careful planning and monitoring of professional development, with the required in-service dates moved to Mondays when the teachers do not have students (Yarbrough and Gilman, 2006).

Three of the schools in the Farbman and Kaplan (2005) study structure the weekly schedule around a longer school day for students Mondays–Thursdays, with an abbreviated day for students on Fridays. This arrangement leaves teachers a solid two- to three-hour time block in which to participate all together in professional development and curriculum-planning sessions.

Timilty Middle School dismisses students from school at 11:50 a.m. on Fridays while teachers remain until 2:00 p.m. to participate in a collaborative professional development session with other teachers in the same subject areas. Science teachers have dedicated time to review the alignment between state standards and each segment of their own curriculum to ensure proper pacing. Math teachers have learned about technology applications for teaching middle school math. Similarly, at Young Achievers, teachers gather for planning and professional development from 1:30 p.m.–4:00 p.m. on Fridays. During the first half hour teachers and other staff participate in a school-wide staff meeting, while the last two hours are reserved for teachers to meet in teams either by grade level or subject to plan and discuss curriculum.

Another example of how schedule changes can create more time for professional development and planning comes from Central Park East Secondary School in New York (Darling-Hammond, 1999). This school organizes 7th- to 10th-grade teachers of interdisciplinary core courses (math and science or humanities) with two groups of students daily for two hours each; (11th and 12th grade teachers offer more specialized courses and advisement for the portfolio assessments students must complete to graduate). The teachers average 7.5 hours weekly for joint planning, in addition to five hours of weekly personal planning time. The bulk of this time comes from a weekly full-morning meeting with their disciplinary teams (while students are engaged in community service placements). Central Park East has implemented several other reforms, notably reduced class size and small learning communities, which may also contribute to the school’s success. But the results are impressive: This urban school’s annual graduation rate is more than 90 percent and it sends more than 90 percent of its graduates on to college (Darling-Hammond, 1999).

Farbman and Kaplan (2005) stress that professional development is especially important when implementing block scheduling, since “teachers do need to rethink how they plan for and organize the class period.” They caution that curriculum and lesson plans must be adjusted so that teachers can learn how to take full advantage of the longer blocks of time.

Models that schools or districts use effectively:

  • Boston’s Roxbury Preparatory Charter School established an eight-hour school day to good effect. Every Roxbury student takes two 50-minute math classes and two 50-minute English classes daily, with each class having a somewhat different focus. In English, for example, one class concentrates primarily on reading, while the other focuses primarily on writing and grammar. The two classes are closely connected and the two individual teachers work together to plan curricula, but the double class structure ensures that students get practice every day in both reading and writing. Similarly, the double math classes at Roxbury allow teachers to cover more material and give students more time to practice basic math skills. One math period centers on math procedures, skills, and operations, while the other addresses problem-solving and the real-world application of math skills (Farbman and Kaplan, 2005).
  • The Edina, Minnesota school reversed bus schedules almost 10 years ago, getting the elementary and middle school students to school first, and the high schools to open later at 8:30 a.m. (Graham, 2000).
  • Newberry Middle School in South Carolina uses a four-block schedule where students spend one block of 90-minutes in language arts, a second block in math, a third alternating in social studies or science, and a fourth in physical education, music or other exploratory classes (Canady and Rettig, 1995b).
  • Cincinnati’s Sellman School uses a 75-75-30 plan for its 180-day calendar. Their year is broken up into two 75-day terms with regular period schedules, followed by a six-week term used for additional instruction for those who haven’t met grade-level objectives and enrichment activities for all students (Canady and Rettig, 1995a).


As school boards and other education officials consider strategies to increase instructional time, two primary logical concerns usually pop up—cost and child care. While cost is typically the primary barrier to such policies, child care concerns are often a close second.


Estimates for the strategies we’ve reviewed vary greatly, though the most expensive option would be lengthening the school year. For example, the National Education Commission on Time and Learning predicted in 1993 that increasing the school year nationally to 200 days would cost between $34.4 and $41.9 billion annually (as cited in Aronson et al., 2005). California’s estimates also show the staggering cost involved in expanding the school year. In 2001, then-Governor Gray Davis proposed an ambitious plan to add 30 days to the middle school schedule, at a projected cost of $770 per student. Though Davis’s political troubles no doubt plagued the proposal’s prospects, its cost—an estimated $100 million in its first year, mushrooming to $1 billion in its third year—also doomed it (Legislative Analyst’s Office, 2001).

Schools in the Farbman and Kaplan study (2005) estimated that expanded schedules at three of the district-run extended-time schools cost between $900 and $1,500 per student, depending on the amount of additional time offered and the staffing strategy used to cover that time. (The researchers note that costs at charter and pilot schools are difficult to compute because of different regulations about staffing and teacher pay.)  By calculating a “cost-per-student hour,” Farbman and Kaplan found that while extended time schools cost more to operate than schools with shorter days, the increase in cost is not directly proportional to the time added. For example, these schools spend from 7 percent to 12 percent more per student, yet they are serving students for 15 percent to 45 percent more time.

Farbman and Kaplan note that schools and districts find creative ways to fund such time extensions by attracting public and private funds. For example, while schools have typically used funds from the federal 21st Century Community Learning Center program to operate after-school programs, the Young Achievers Science and Mathematics Pilot School in Boston integrates this funding into the school budget to pay for a longer school day for all students.

The expenses associated with year-round schedules differ dramatically, depending on whether the programs are single-track or multi-track, offer mandatory or voluntary intersessions, affect teacher and other staff contracts, and impact transportation and other school services. Facility issues such as air conditioning and janitorial staff requirements are also factors that may affect year-round costs.

Single-track year round schools: Depending on the size and location of the school or district considering a modified calendar, air conditioning, transportation, and staffing costs may increase regardless of whether intersession programs are offered. In schools that are offering intersession programs, some have partnered with nonprofit organizations in their community to provide intersession activities at little to no cost. An interesting example of this is the partnership between Alexandria City Public Schools and Share the Wind Sailing School, which offers two-week intersession programs to students on a modified calendar at the Mount Vernon Elementary School. (Parents pay a nominal $25 fee for the two-week program.)

Multi-track year round schools: Because this approach addresses overcrowding, the increased capacity for schools is largely dependent on the number of tracks used. Schools using three tracks can increase capacity by 33 percent, those using four tracks can gain 25 percent, and those using five tracks can reach a 20 percent increase (California Department of Education, 2006). The cost savings per student is greater as capacity increases, according to the California Department of Education (CDE) (2006), as shown in Table 3, which estimates the costs incurred by adding additional students through a multi-track year-round schedule at a school with a capacity of 500 students. Until the enrollment increases by 25 percent (from 500 to 635), the cost per pupil is still cheaper using a traditional calendar with additional facilities (such as trailers).

Table 3
Estimated Cost Per Pupil for Multi-Track, Year-Round Schedules
Position/Item Cost Enrollment of 500 Students   Enrollment of 581 Students   Enrollment of 635 Students  
Traditional  Year-Round  Traditional  Year-Round  Traditional  Year-Round 
Personnel $224,484  $251,459  $224,484  $251,459  $224,484  $251,459 
Additional Facilities  $0  $0  $28,178  $0  $46,960  $0 
Utilities  $34,546  $44,816  $36.562  $44,816  $40,578  $44,816 
Supplies  $11,850  $11,850  $13,650  $13,650  $15,450  $15,450 
Total Cost  $270,880  $308,125  $302,874  $309,925  $327,472  $311,725 
Cost Per Pupil $542  $616  $521  $533  $515  $490 
Source: California Department of Education
Note: Year-round personnel costs include increased time for principal, clerical staff, aides, and custodial staff and their corresponding fringe benefits

However, CDE (2005) also notes that the use of multi-track, year-round schools can alleviate new capital costs for building new facilities. In 2005, the state estimated that if existing multi-track, year-round schools increased capacity by at least 20 percent, more than $2.5 billion in construction costs would be avoided by the state and local school districts.

Another study (Pechman, O’Brien, and Mullens, 1995) estimated that a moderate-sized suburban school district would save between 5 percent and 6 percent of system-wide costs by implementing a multi-track, year-round calendar. Yet the bulk of the savings emanates from minimized new school construction (and resulting debt reduction). Savings would be greatest if the district closed under-used schools, maximized the bus system’s efficiency by using geographically zoned tracks, and minimized the number of extended contracts and administrative staff increases.

Block scheduling: Few of the studies on block scheduling address the cost or cost-effectiveness of this strategy. Canady and Rettig (1995b) note that administrators often assume that block scheduling will require staff increases. Yet the impact on staffing (and therefore cost) depends on the number of classes currently offered, the number offered through the proposed block schedule, and the contractual arrangements in place for teaching staff. A change in class size or staffing may be necessary, they state.

One study of a small town high school in the western United States found that costs increased over a ten-year period after block scheduling was implemented, but these increases also coincided with a gain in the student population (Lare, Jablonski, and Salvaterra, 2002). Although academic data indicated no positive or negative impact from block scheduling, Lare et al. found positive reactions from both teachers and students, and this perception, along with the fact that the schedule change had enabled a wider number of courses to be offered, led them to conclude that block-scheduling was “cost-effective” (Lare et al., 2002).

Four-day school week: This strategy is typically implemented to save districts and schools money. Participating Colorado districts saved 20 percent in transportation and food service costs. Yet the state department of education warns that this level of savings is only possible if districts severely restrict or eliminate transportation for activities or programs not conducted on regular school days (Dam, 2004). Other districts may not reach the same level of savings, as noted by Kentucky’s Webster County district, which only incurred an annual savings of approximately three percent of the school board’s general fund budget (Yarbrough and Gilman, 2006).

Child Care

Another primary concern regarding school schedules is the impact on child care for children of working parents. Generally, lengthening the school day or year lessens the amount of time needed for child care. Yet some of the nontraditional schedules—year-round or four-day school week schedules—cause scheduling problems for working parents. To address this concern, many year-round schools (both single- and multi-track) have offered intersession programs and partnered with community agencies to ensure that children are not left unattended.

In Colorado, child care did not appear to be a problem in those districts with four-day school week schedules (Dam, 2004). The author hypothesized that with longer school days, working parents did not need child care during the four school days, and most parents were able to find the necessary childcare for the fifth day. (High school students were available since schools were closed, or it was easier to arrange for a single full day of childcare than for a couple of hours five days per week.)

Things to consider

In considering any of the scheduling alternatives presented in this brief, your board must do its homework and examine the needs of your individual district or school, in addition to how a schedule change will address those needs. The following suggestions are adapted from the Northeast and Islands Regional Educational Laboratory (1998).

Consult external resources: Visit schools and other communities that are actively involved in the scheduling change you’re considering to observe their classes and to speak directly with those affected by the new schedule.

Involve all stakeholders: Ownership of a new schedule or strategy occurs when everyone is invited to give input—teachers, administrators, students, and parents. Success with a new schedule depends on the involvement of all participants in the transformation and a sense that each constituency has its voice heard. Surveys, interviews, focus groups, and informal discussions can help.

Provide professional development: As with any new program, the needs of teachers should be determined and addressed throughout the year. This is especially important for block scheduling, as teachers may need to learn new strategies for presenting information in a number of different formats.

Seek constant feedback: Evaluate the schedule change through formal and informal methods. For example, collect feedback from teachers, students, and parents through community-wide or school-wide forums, surveys, or focus groups.

Collect and maintain data on teacher and student performance: Use data to monitor what is and is not working, and share the information with teachers and staff.

Make a long-term commitment: Recognize that a new strategy or schedule requires sufficient trial time and develop a multi-year implementation plan. As Northeast Regional Educational Laboratory notes, “Some problems at your school will not surface during the first year; similarly some of the benefits will take time to emerge and develop before tangible results are evident.”

Ensure that schedule changes are incorporated into broader goals for the district and the school: It is important to ask yourself the following questions when assessing a time or schedule change: How does it fit into your overall plan for school improvement? How does it integrate with other teaching and learning strategies? Has your school laid the groundwork for its successful implementation? Is there a plan for measuring progress?

 This document was prepared for the Center for Public Education by Eileen M. O'Brien, an independent education researcher and consultant in Alexandria, Virginia. Much of O'Brien's work has focused on access to quality education for disadvantaged and minority populations. She has a master of public administration from George Washington University and a bachelor of science degree in psychology from Loyola University of Chicago.

Posted: September 25, 2006

© 2006 The Center for Public Education

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