User Guide for the TIMSS International Database.pdf - TIMSS and ...

P E R F O R M I N G A N A L Y S E S C H A P T E R 9
9.5 Performing Analyses with Teacher-Level Variables
When analyzing the teacher data, it is first necessary to link the students with their
corresponding teachers. Each student record in the Student Background data file can contain
a link to as many as six different teachers in the Teacher Background data file. To facilitate
the linking between students and their teachers in the teacher file, the Student-Teacher
Linkage file was created and is part of the International Database. This file is called
ALG1 in Population 1 and BLG1 in Population 2. The Student-
Teacher Linkage file contains one record for each student-by-teacher combination, with the
corresponding identification variables. Each record also contains the number of mathematics
and science teachers for the student and a set of weights that can be used when conducting
analyses with these data. In order to simplify the merging process for analyses that link
teacher variables to student achievement, student achievement scores, sampling weights, and
JRR replication information have been added to the Student-Teacher Linkage file. For such
analyses it is necessary only to merge the Teacher Background file with the Student-Teacher
Linkage file. For analyses linking teacher variables to other student variables, it is necessary
also to merge the Student Background files to the other two.
Conducting analyses with the teacher data requires some extra steps that are not required
when analyzing the student or school background data. The code in SAS and SPSS for the
example that follows is presented in Figures 9.13 and Figure 9.14. For our example, we want
to find out about the years of experience of the mathematics teachers that teach the eighthgrade
students in each of the TIMSS countries. In particular, we want to find out what percent
of eighth-grade students are taught by teachers of specific groups based on their years of
experience, and the mean achievement in mathematics of the students taught by those
teachers. These are the results that are presented in Figure 9.2 earlier in this chapter.
The TIMSS teacher files do not contain representative samples of teachers within a country.
Rather, these are the teachers for a representative sample of students within a country.
Therefore, it is appropriate that statements about the teachers be made only in terms of how
many students are taught by teachers of one kind or another, and not in terms of how many
teachers in the country do one thing or another.
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