The Effects of Block Scheduling

Two leading authorities describe what results when high schools use alternative schedules by MICHAEL D. RETTIG

As educators have investigated ways to use time more productively, major changes have been occurring in high school schedules. One especially attractive option has been block scheduling, which is in place in roughly 30 percent of the nation’s secondary schools.

Research now is emerging about the impact of the two most common alternative high school scheduling models.

Several factors have influenced changes in high school schedules during the last decade. In various states the number of course credits required for graduation with an academic diploma increased to as many as 24 Carnegie units. In schools with a traditional six- or seven-period day, this left little room in schedules for fine arts or vocational education electives. To preserve students' options, many high schools added periods to the schedule.

However, students often became overwhelmed by the experience of adjusting to eight or more teachers in one day and juggling multiple assignments and tests over a full school year. By adding class periods without lengthening the school day, the length of class sessions was reduced to as little as 36 minutes in some schools. Teachers and students complained about the difficulty of working productively in such short, fragmented time periods.

The shorter class sessions exacerbated existing problems in hands-on courses, such as art, laboratory science and physical education. How could teachers in these fields conduct any meaningful activity in 40 minutes or less? Technology teachers found it nearly impossible to settle students into a computer lab and have them log on to investigate a complicated issue on the Internet.

Many teachers and administrators also argued that an impersonal environment was created by the assembly-line, single-period daily regimen and that student discipline was affected adversely by schedules that released thousands of students into hallways six to 10 times a day for three to five minutes of chaos. A 1994 report by the National Education Commission on Time and Learning indicated that traditional ways of organizing schools contributed to these problems; the report referred to students as "prisoners of time."

Two Likely Routes
One response to these concerns has been block scheduling. While about one in three high schools today operate some form of block schedule, in some states the number is much higher. In states such as Virginia and North Carolina, more than two-thirds of the high schools use alternative schedules.

Although several hybrids and modifications of block scheduling exist, almost all represent some variation of two basic forms--the alternate-day schedule and the 4/4 semester schedule.

In the alternate-day, or what some call the A/B schedule, classes meet every other day for 80-110 minutes, or approximately double the length of an instructional period in the traditional schedule. The A/B schedule typically comes in six-, seven- and eight-course formats.

In the pure 4/4 schedule, students complete four year-long courses each semester. Most courses meet for 80-100 minutes every day over a 90-day semester. Students typically earn eight credits per year, allowing them to complete up to 32 credits during their four years in high school.

Three Generalizations
The research on high school block scheduling can be organized into three topical threads: effects on school climate, effects on academics and critical factors affecting the change to a block schedule.

Three important generalizations about block scheduling appear certain:


  • The A/B schedule is easier to implement than the 4/4 semester schedule, both politically and administratively;



  • In almost all cases, the 4/4 schedule must be adapted to allow some courses to run year-long; and



  • Merely changing the school bell schedule will not guarantee better student performance.


  • Effects on Climate
    The majority of teachers, administrators, students and parents are favorable to block scheduling, even after the sometimes difficult period of change. Initially, teachers report feeling greater stress until they learn how to plan for and teach in an extended block of time, but eventually both teachers and students report school becomes less stressful.

    In nearly all of the more than 100 case studies, dissertations and reports completed on block scheduling, the number of discipline referrals to the office is reduced, typically between 25 and 50 percent. Evidence also exists that in-school suspensions decline, that teacher and student attendance improves slightly and, for obvious reasons, the number of class tardies is reduced.

    Unless special plans are made, students may experience difficulty recovering from class absences. However, there are some indications that, because of this factor, the more motivated students have fewer absences. To date, we find it unlikely that students who avowedly dislike school attend more often simply by offering them a different schedule. Overall, though, we found a slight increase in student attendance.

    Effects on Performance

    Effects on academics have been investigated primarily by studying the following: grade point average, honor roll achievement, numbers of failures and dropout rates and students' performance on standardized tests. Except in North Carolina and Canada, few large-scale studies of block scheduling have been undertaken so much of the data reported is based on individual school evaluation reports and dissertations.

    Consistent evidence shows that students' grades improve and the number of students on the honor roll increases. Some evidence suggests that both improvements are greater in 4/4 schools than in A/B schools. Studies show declining failure rates in 4/4 schools and a greater likelihood that students labeled "at risk" will remain in school, especially in the 4/4 schedule, probably because students may repeat several classes but still graduate with their class.

    In addition, the 4/4 schedule provides new instructional flexibility. For example, many schools in Virginia have begun to offer Algebra I as a full-block, year-long class to enhance at-risk students' chances of passing a statewide end-of-course exam. Parallel to these findings are limited data that suggest graduation rates are more likely to increase under the 4/4 plan than under the A/B plan.

    When considering the effects of block scheduling, considerable controversy has arisen regarding studies reporting "hard data" on student achievement, specifically performance based on standardized measurements. To date, most studies on student achievement have been focused on the 4/4 schedule. However, one recent study in Virginia compares single-period, A/B and 4/4 schedules.

    We believe the key questions regarding studies related to student achievement in block-scheduled schools should include the following: What evidence is provided that measurements are valid and reliable? What attempts were made to control for other variables that might influence test scores, such as socioeconomic status, prior achievement level and consistency of testing conditions?

    In North Carolina, researchers compared the performance of block and non-blocked schools in a systematic fashion through the use of statewide, end-of-course examinations in Algebra I, English I, biology, U.S. history and a social studies course titled "Economics, Legal and Political Systems." Data have been compiled for three years of end-of-course testing.

    Researchers used two controls to equalize the populations taking the tests. Overall, schools adopting the 4/4 had a lower "starting point," meaning their test scores in nearly every area were lower prior to block scheduling than were scores of non-blocked schools. In addition, early adopters of the 4/4 also served a population with an overall lower socioeconomic status. The study reported: "Overall, students in block and non-block scheduled schools have equivalent end-of-course test scores." Yet, it should be noted that while scores were equivalent, students in 4/4 schools earned eight credits per year, while students in most single-period schools earned six or at most seven credits per year.

    Comparisons With Canada
    Several Canadian studies have compared achievement for students in semester schedules and students who take courses in year-long, single periods. In a study frequently cited by critics of block scheduling, David J. Bateson of the University of British Columbia reported significantly lower achievement in science as measured by a 40-item multiple-choice test given in 1986 to secondary school students in British Columbia operating on the 4/4 schedule. The conclusions and educational significance of this study have been questioned for the following reasons:


  • The testing timetable favored students in year-long classes. The examination was given to all students in May, regardless of when they took science that year. For students who had completed the class during the fall semester, the exam was taken nearly a full semester after finishing the course. Spring semester students missed two days of instruction for every one day missed by full-year students. The testing time frame itself could have had an effect upon the results.



  • Considerable doubt exists as to whether the groups of students being compared were equivalent. Evidence in the United States suggests that before the adoption of the new schedule, 4/4 schools had lower average test scores and served a lower SES population than the comparison schools that remained on the single-period schedule. Schools satisfied with students' academic performance have been less likely to change their schedules. The differences in populations caused by this "volunteer effect" could account partially for the differences in achievement reported.



  • Important differences exist in the way U.S. and Canadian educators implement the 4/4 semester block schedule. In Canada, blocks range from 60 to 80 minutes in length. In the United States, we know of only one 4/4 school with fewer than 80 minutes per block, and most have classes of 85 to 90 minutes. In Canada, it appears little staff development was provided to teachers in how to adapt instruction and course pacing--training that has been stressed in most successful U.S. implementations. Teachers in Canada often were provided planning time only one semester, while U.S. teachers generally have been allocated one of four blocks for lesson planning each semester.


  • Questions About Retention
    The long-term effect of the 4/4 schedule on student retention of learned material, which is an issue especially with teachers of mathematics and foreign languages, remains a matter of contention. Steven Kramer, who completed a review of 25 years of research relating block scheduling to mathematics achievement for his doctoral work at University of Maryland, stated: "It seems safest to conclude that a gap in instruction may reduce recall of recently learned material but that it will probably have no long-term negative effects on student learning."

    Many schools report greater numbers of students enrolled in Advanced Placement classes with stable or increasing pass rates. The College Board has reported that students in the 4/4 schedule who take AP courses for only one semester score lower on some AP examinations than do students who are enrolled in courses for the entire academic year.

    The performance of students in AP classes in the 4/4 schedule also may be more a testing issue than a learning issue. Students who have completed an AP course in the fall must wait until May to take the exam, while students in some school districts who are enrolled in the spring semester are tested long before the course is completed. Also, the comparison released by the College Board did not control for economic differences among the schools or for previous test scores at those schools.

    In addition, students in block-scheduled schools where AP courses were extended over two semesters were classified with the year-long comparison group. Because of the emphasis on AP scores, the fixed May testing date for AP courses has forced many schools in the 4/4 plan to make special adaptations.

    Special Course Concerns
    Schools that adopt a block schedule are more successful when they address several key implementation issues: the decision-making process, the actual construction of the schedule, the commitment to sustained staff development and the creation of a responsive monitoring and evaluation process.

    Teachers and parents are more positive toward block scheduling when they have been involved in the decision-making process. We have found that a schedule change mandated through administrative edict to have a negative effect on the implementation.

    The actual design of the master schedule is a second determining factor of long-term success. A pure 4/4 schedule is rarely appropriate, meaning adaptations will be needed to meet the needs of a variety of disciplines and specialized courses.

    Consider the scheduling of performing arts classes within the 4/4 plan. Evidence indicates that enrollment in these courses may decline if the 4/4 schedule is not adapted to allow year-long participation without allocating two credits each year to band, orchestra, and choir. Through modifications, such as a split block or an embedded A/B schedule, it is possible to maintain both instructional quality and enrollment. Similar issues must be addressed with AP courses, journalism, yearbook, special education and some vocational education classes.

    A second important scheduling concern relates to the instruction of foreign language. In both the A/B and 4/4 plans, foreign language teachers report difficulty covering the equivalent of two classes of material during a double-length period. There is evidence, however, that more intense instruction produces greater learning in foreign language. Thus in the 4/4 schedule we recommend that sequencing be arranged so that students may complete the first two years of a foreign language in consecutive semesters, preferably in the same academic year. This recommendation is based on the premise that the second year of a language is the most critical and has the highest failure rate of any of the 4-5 years of language instruction.

    Schools also should develop clear goals and expectations for the schedule. Specify the criteria for determining which classes must be scheduled on a year-long basis. We have found 4/4 schools in some states where two credits and a year-long block have been allocated to electives such as cheerleading, drill teams, drama, and sports. By extending all of those electives for a full block both semesters, students quickly fill up their schedules.

    This practice becomes a major problem with parents and students by the third year a school is in the 4/4 schedule as students' choices are reduced. We suggest that such classes be embedded in the 4/4 schedule on an A/B basis.

    Creating Lesson Plans
    The third key to successful implementation of block scheduling is sustained staff development. Most teachers in block-scheduled schools plan lessons that include at least three different approaches or activities. For example, during one block a teacher might provide a short lecture to explain a new concept, an activity that asks students to apply that concept and several questions that review material and ask students to synthesize the explanation and application.

    The most difficult aspects of a lesson plan for high school teachers seem to be the development of appropriate activities for the application phase of a lesson and the management of pacing and transitions. Just providing teachers with assistance with various teaching strategies is not sufficient. Many teachers also need help in building those strategies into appropriate lesson plans. Therefore, we highly recommend that staff development include both generic and subject-specific assistance.

    Finally, the fourth key to successful implementation is the design and implementation of a comprehensive monitoring and evaluation plan. A variety of data should be collected and analyzed on an annual basis. Decisions regarding schedule revisions and the need for specific staff development activities should be informed by these data.

    Potential Impact
    In reviewing the data collected about block scheduling, overwhelming evidence bolsters the view that a school environment can be affected positively by either an A/B or a 4/4 schedule. Sufficient data suggest that students' academic performance is not harmed and many individual schools, based on several selected variables, have reported increases in student performance.

    We realize that block scheduling alone is not a panacea for the problems in American education. However, a school schedule can have an enormous impact on a school's instructional climate. We believe that hundreds of high schools across the nation have reaffirmed what we stated five years ago that scheduling is an untapped resource that can serve as a catalyst for major school improvements. Clearly there is sufficient evidence to encourage the journey to continue.

    Michael Rettig is an associate professor of education at James Madison University, MSC 1903, Harrisonburg, VA 22807. E-mail: rettigmd@jmu.edu. Robert Lynn Canady is a professor of educational leadership and policy studies at University of Virginia.