© 2001 International Association for the Evaluation of Educational Achievement (IEA)
The TIMSS science achievement scale summarizes student performance on test items designed to measure a wide range of student knowledge and proficiency. In order to provide meaningful descriptions of what performance could mean in terms of the science that students know and can do, TIMSS identified four points on the scale for use as international benchmarks(5) or reference points, and conducted an ambitious scale anchoring exercise to describe students performance at these benchmarks. Exhibit 1.3 shows the four international benchmarks of science achievement and briefly describes what students scoring at these benchmarks typically know and can do. More detailed descriptions appear in Chapter 2, together with example test items illustrating performance at each benchmark.
The Top 10% Benchmark is defined at the 90th percentile on the TIMSS science scale, taking into account the performance of all students in all countries participating in 1999. It corresponds to a scale score of 616 and is the point above which the top 10 percent of students in the TIMSS 1999 assessment scored. Students performing at this level demonstrated a grasp of some complex and abstract science concepts in earth science, life science, physics, and chemistry, and showed an understanding of the fundamentals of scientific investigation.
The Upper Quarter Benchmark is the 75th percentile on the science scale. This point, corresponding to a scale score of 558, is the point above which the top 25 percent of students scored. Students scoring at this benchmark typically demonstrated conceptual understanding of some science cycles, systems, and principles.
The Median Benchmark, with a score of 488, corresponds to the 50th percentile, or median. This is the point above which the top half of students scored on the TIMSS 1999 assessment. Students performing at this level typically were able to recognize and communicate basic scientific information across a range of topics.
The Lower Quarter Benchmark is the 25th percentile and corresponds to a scale score of 410. This score point is reached by the top 75 percent of students and may be used as a benchmark of performance for lower-achieving students. Students scoring at this level typically could recognize some basic facts from the earth, life, and physical sciences presented in non-technical language.
Exhibit 1.4 displays the percentage of students in each participating entity that reached each international benchmark, in decreasing order by the percentage reaching the Top 10% Benchmark. If student achievement in science were distributed alike in every entity, then each entity would be expected to have about 10 percent of its students reaching the Top 10% Benchmark, 25 percent the Upper Quarter Benchmark, 50 percent the Median Benchmark, and 75 percent the Lower Quarter Benchmark. Although countries such as Latvia (LSS),(6) Italy, Israel, Malaysia, and Lithuania, and Benchmarking participants such as the Delaware Science Coalition, came fairly close, no entity followed this pattern exactly. Instead, the high-performing entities generally had greater percentages of students reaching each benchmark, and the low-performing entities had lesser percentages.
Among the high performers, for example, the Naperville School District, Singapore, and Chinese Taipei had more than 30 percent of their students reaching the Top 10% Benchmark, more than half reaching the Upper Quarter Benchmark, four-fifths or more reaching the Median Benchmark, and almost all (94 percent or more) reaching the Lower Quarter Benchmark.
In contrast, the four lowest-performing Benchmarking participants, all urban districts, had no more than four percent of their students reaching the Top 10% Benchmark, 10 to 12 percent reaching the Upper Quarter Benchmark, and just about one-third reaching the Median Benchmark. The lowest-performing countries of South Africa and Morocco had almost no students reaching the Top 10% Benchmark, only one or two percent reaching the Upper Quarter Benchmark, five or six percent reaching the Median Benchmark, and no more than 20 percent reaching the Lower Quarter Benchmark.
Although Exhibit 1.4 is organized to draw particular attention to the percentage of high-achieving students in each entity, it conveys information about the distribution of middle and low performers also. For example, several countries, including Belgium (Flemish),(7) Hong Kong, Malaysia, Lithuania, and Thailand, had greater percentages of students reaching the Median and Lower Quarter Benchmarks than might be expected from their percentages of high-performing students.
TIMSS 1999 Benchmarking is a project of the
International Study Center
Boston College, Lynch School of Education