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appendix a: overview of pirls 2006 procedures
for each country, four attributes of the populations sampled in 2001 and
2006: number of years of formal schooling, average student age, the score on
the United Nations Development Programme’s (UNDP) human development
index, and the percentage of students in the national desired population
excluded from the assessment. Most countries and provinces were very
similar with regard to these attributes across the two assessments, although it
is noteworthy than the Russian Federation and Slovenia underwent structural
changes in the age at which children enter schools that are reflected in their
samples. In 2001, the Russian sample contained third-grade students from
some regions and fourth-grade students from others, whereas all students
were in fourth grade in 2006. Slovenia is in transition toward having all
children begin school at an earlier age so that they all will have four years of
primary schooling instead of three years, as was the case in 2001. However,
the transition was not complete in 2006.
For analysis and reporting, students’ questionnaire data, along with
questionnaire data from their parents, teachers, and school principals, were
linked to students’ achievement data. Exhibit A.9 shows the percentage of
students with available student, parent, teacher, and principal questionnaire
data. Although the vast majority of students in PIRLS 2006 were taught by a
single teacher, there were some students in some countries taught by more
than one teacher. The percentage of students in each country taught by one,
two, or three teachers is presented in Exhibit A.10. Only Scotland, Sweden,
and the Canadian province of British Columbia had more than 10 percent of
students with more than one teacher—21 percent, 13 percent, and 13 percent,
respectively. If a student had more than one teacher, the student’s data
record was replicated so that there were as many student records as there
were teacher records. Then each teacher record was merged with one of the
student records. So as not to over count the student in analyses, the sampling
weight for each student record was divided by the number of records that the
student had. For example, if a student had two teachers, the student’s record
was replicated so that there were two records, and the first was merged with
one teacher record and the second with the other teacher record. Each of the
two student records was given half of the original student’s weight.
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