Disentangling the Effects of the School Year from the School Day: Evidence from the TIMSS Assessments

Abstract

Schools often have to decide between extending the length of the school year or the school day. This paper examines the effects of changes in the distribution of instructional time on eighth-grade student achievement through a methodological framework that disaggregates total yearly instructional time into separate inputs for days per year and hours per day. This study's dataset brings together nearly 900,000 student observations across eighty countries and four quadrennial testing cycles of the Trends in International Mathematics and Science Study (TIMSS) Assessments (1995–2007). I find that the positive effects of instructional time on student achievement are driven largely by the length of the school day and not by the length of the school year, with diminishing marginal returns to the former. Socioeconomically underprivileged students are most likely to realize gains from a longer school day. Furthermore, isolating the amount of instructional time spent on TIMSS-tested subjects from the rest of the school day reveals spillover effects from time spent in non-tested subjects that are especially meaningful for underprivileged students. In contrast, the effects of time spent in tested subjects are more homogeneous across student groups.

More time at school

“…While the extent of the increase differs for each grade, this increase translated into an approximate addition of 280 lessons per year, on average, or 7 hours per week for all students in compulsory education, from the mandatory pre-school year to the end of lower secondary education (World Bank, 2019 [139]). Based on these minimum number of lessons, students will typically be in school for 6 to 7 hours a day, with the day ending usually around 14:00 for the youngest students, and 15:00 for the oldest students, although some days may be shorter, and others longer, depending on the decision of the school (UVM, 2020 [138]).…”

“…Essentially, the longer and more varied school day provides more time for the teaching of subject-divided lessons, in particular Danish and mathematics, but also other subjects, such as English, nature and technology, and music; introduces the concept of and dedicated time for "supported learning"; and integrates daily sports, exercise and movement as well as homework assistance into the school day (Figure 11). Further changes were introduced as part of the extended day to ensure students reach high standards through their learning, for instance through a clarification and simplification of the Common Objectives; more freedom to offer electives and to introduce elite sports and talent music classes; the greater involvement of local sports clubs, cultural centres and businesses ("an open school"); the competency development of school boards to increase parent and student involvement; and measures for a better classroom climate (Nusche et al, 2016[134]; World Bank, 2019 [139]).…”

“…The introduction of a longer and more varied school day sought to increase the time allocated to learning, both through subject-divided lessons and additional time for supported learning during the remainder of the school day (Houlberg et al, 2016[135]). These changes were designed to give municipalities and schools the possibility to organise teaching in innovative and better ways, for example through teaching within but also across subjects (World Bank, 2019 [139]). Concerning time for learning in subject-divided lessons, the Folkeskole Act stipulates how many hours the students must have in selected subjects per year, namely Danish and mathematics (for all grades) and history (for Grades 3 to 9).…”

“…Activities typically take three forms: additional time connected to subject-divided lessons, separate activities during the school week that go beyond the traditional subjects, entire school days dedicated to specific elective courses. The time available for supported learning is the time left after subject-specific teaching and breaks (World Bank, 2019 [139]; UVM, 2020 [138]).…”

“…These activities can be integrated in regular classes or supported learning (e.g. morning runs, ball games or using movement pedagogically to work with content), or be provided in the form of more extended and continuous activities in collaboration with the local community (Houlberg et al, 2016[135]; World Bank, 2019 [139]).…”