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Chapter 2 © 2001 International Association for the Evaluation of Educational Achievement (IEA)


What Are the Gender Differences in Science Achievement?Exhibit 1.5 presents average science achievement separately for girls and boys for each of the participating entities, as well as the difference between the means, in increasing order of the difference. The gender difference for each entity is shown by a bar indicating the amount of the difference, whether its direction favored girls or boys, and whether it is statistically significant (a darkened bar). It is disappointing that in science at the eighth grade, the TIMSS 1999 Benchmarking Study shows relatively unequal average achievement for girls and boys in many of the Benchmarking jurisdictions, and in the United States overall. Boys had significantly higher average science achievement than girls in 10 of the 13 Benchmarking states, with Massachusetts, South Carolina, and Texas the exceptions. Gender differences were less prevalent among the Benchmarking districts and consortia, with significant differences in just four jurisdictions: the First in the World Consortium, Guilford County, Naperville, and the Southwest Pennsylvania Math and Science Collaborative. On average across all TIMSS 1999 countries, there was a significant difference of 15 scalescore points favoring boys, although this varied considerably from country to country. Differences large enough to be statistically significant were found in 16 of the 38 countries, including the U.S. Exhibit 1.6 provides information on gender differences in science achievement among students with high performance compared with those in the middle of the achievement distribution. For each entity, score levels were computed for the highestscoring 25 percent of students, called the upper quarter level, and for the highestscoring 50 percent, called the median level. The percentages of girls and boys in each entity reaching each of the two levels were computed. For equitable performance, 25 percent each of girls and boys should have reached the upper quarter level, and 50 percent the median level. As may be seen from Exhibit 1.6, in all Benchmarking states but Maryland, Massachusetts, and South Carolina, the percentage of boys reaching the upper quarter level was significantly greater than the percentage of girls. There was a significantly greater percentage of boys reaching the median level in all states but Connecticut, Massachusetts, and South Carolina. Among the Benchmarking districts and consortia, significantly greater percentages of boys reached the upper quarter level in the First in the World Consortium, Guilford County, and the Southwest Pennsylvania Math and Science Collaborative. Only in the latter did a significantly greater percentage of boys reach the median level. The gender difference in science at the country level is more apparent among highperforming students, although internationally it was about the same at both the upper quarter and median levels. On average across countries, 29 percent of boys reached the upper quarter level, compared with 21 percent of girls, a statistically significant difference of eight percentage points. Similarly, the international average percentage of boys reaching the median level was 54 percent and of girls 46 percent, also a significant difference of eight percentage points. Perhaps more important, however, Exhibit 1.6 shows that in 21 countries the percentage of boys reaching the upper quarter level was significantly greater than the percentage of girls, whereas this was the case in 13 countries at the median level. In no country did the percentage of girls reaching either level significantly exceed the percentage of boys. The gender differences found among the Benchmarking states are consistent with the results of TIMSS in both 1995 and 1999, which showed a pervasive difference in science achievement favoring boys, far more evident than in mathematics.(8) They are also consistent with the results from the second iea science study conducted in 198384, which for 14yearolds found standard score differences favoring boys in all 23 of the participating countries.(9)

TIMSS 1999 Benchmarking is a project of the
International Study Center
Boston College, Lynch School of Education