Scale scores are derived from responses to assessment items that summarize the overall performance attained by that respondent. The scale scores represent degrees of proficiency in a particular domain. They offer the opportunity to examine the relationships between student performance and various factors measured.
In large-scale surveys such as the Trends in International Mathematics and Science Study (TIMSS), National Assessment of Educational Progress (NAEP), and International Adult Literacy and Life Skills Survey (IALLS), since each respondent responded to just a subset of the assessment items, multiple imputations were used to derive reliable estimates of student performance on the assessment as a whole. Students’ proficiencies are generated using as input the students’ responses to the items they were given, the item parameters estimated at the calibration stage, and the conditioning variables. The TIMSS eighth-grade reporting metric was...