© 2001 International Association for the Evaluation of Educational Achievement (IEA)
How Much School Time Is Devoted to Science Instruction?
Exhibit 6.4 presents information about the amount of instruction in the sciences given to eighth-grade students in the TIMSS 1999 Benchmarking jurisdictions and the comparison countries. Since different systems have school years of different lengths (see Exhibit R3.6) and different arrangements of weekly and daily instruction, the information is given in terms of the average number of hours of science instruction over the school year as reported by science teachers.
Across countries where science is taught as a single subject, the average yearly instructional time for science was 122 hours, representing 12 percent of the total instructional time for all subjects. In general, students in countries with separate science subjects had more total instructional hours in the sciences, with over 220 hours in the Russian Federation and the Czech Republic, for example. Since these students study all of the subjects offered, the total time is the sum of the hours reported by each subject area teacher. In the United States, the average instructional time in science for eighth-grade students was 144 hours. Benchmarking entities that reported more than 160 hours were North and South Carolina, the Michigan Invitational Group, the Fremont/Lincoln/Westside Public Schools, Missouri, and the Academy School District. Entities reporting 120 hours or less were the Naperville School District, the Southwest Pennsylvania Math and Science Collaborative, and the Jersey City Public Schools.
Among the comparison general-science countries, the percentage of instructional time at the eighth grade devoted to the sciences ranged from 19 percent in England to six percent in Italy. In comparison, it ranged from 18 percent in the Michigan Invitational Group to 12 percent in five districts and consortia. Among the selected separate-science countries, the percentage was as high as 24 percent in the Czech Republic and 26 percent in the Russian Federation.
As shown in Exhibit 6.5, teachers of about 60 percent of the students in the single-science countries, on average internationally, reported that science classes meet for at least two hours per week but fewer than three and a half hours. For another 17 percent, classes meet for at least three and a half hours but fewer than five On average, eighth graders in the United States spend more time in science class per week (61 percent spend three and a half to five hours) than do their counterparts in other general-science countries. This pattern of mostly three and a half to five hours held for nearly all of the Benchmarking entities, with the exception of North Carolina (primarily five hours or more), the Chicago and Jersey City Public Schools, and Naperville (the latter three primarily two to three and a half hours).
The data, however, reveal no clear pattern between the number of in-class instructional hours and science achievement either across or within participating entities. Common sense and research both support the idea that time on task is an important contributor to achievement, yet this time can be spent more or less efficiently. Time alone is not enough; it needs to be spent on high-quality science instruction. Devoting extensive class time to remedial activities can deprive students of this. Also, instructional time can be spent out of school in various tutoring programs; low-performing students may be receiving additional instruction.
Videotapes of mathematics classes in the United States and Japan in TIMSS 1995 revealed that outside interruptions like those for announcements or to conduct administrative tasks can affect the flow of the lesson and detract from instructional time.(3) As shown in Exhibit 6.6, on average internationally almost one-quarter of the students (23 percent) in general-science countries were in science classes that were interrupted pretty often or almost always, and 28 percent were in classes that were never interrupted. The percentage was generally lower in the separate-science countries. In Japan and Korea, more than 60 percent of students were in science classes that were never interrupted compared with only 13 percent in the United States. In the United States, nearly one-third of the eighth graders were in science classes that were interrupted pretty often or almost always. If anything, the teachers in most of the Benchmarking jurisdictions reported even more interruptions than did teachers in the US overall. The jurisdictions with 20 percent or more of students in classrooms that were never interrupted were the First in the World Consortium, Montgomery County, and Naperville. Conversely, the jurisdictions with the highest percentages of students in classrooms almost always interrupted (17 to 20 percent) were the public school systems of Jersey City, Miami-Dade, and Rochester. Students in science classrooms that were frequently interrupted had substantially lower achievement than their counterparts in classrooms with fewer interruptions.
TIMSS 1999 Benchmarking is a project of the
International Study Center
Boston College, Lynch School of Education