TIMSS Advanced 2015 Data
All statistics were computed using sampling weights.
All achievement data are presented as five plausible values. All required statistics were calculated separately for each of the plausible values and the resulting statistics averaged to get the final result. This can be done efficiently using IEA IDB Analyzer.
Standard errors for significance testing of achievement results should be computed using the:
- Jackknife repeated replication method (JK2 variant) to estimate sampling variance, and
- Differences between the five plausible values to estimate measurement variance.
For secondary analyses, data can be analyzed with IEA IDB Analyzer. This tool takes into account the characteristics of the sampling and assessment design and implements the jackknife replication method with the appropriate plausible values.
General note: TIMSS Advanced data are designed for group-level reporting; students’ scale scores in the database are not intended to report performance of individual students or very small groups.
- Background questionnaires (school, teacher, and student)
- Curriculum questionnaires
- Achievement responses to assessment items (see below under item release policy)
- Scoring reliability
- Test-curriculum matching analysis (TCMA) data
Responses to all items used in the assessment are included in the database; after each cycle, some of the items are made available for restricted use by the public. The remaining items are kept secure, thus ensuring the possibility of measuring trends over time. Access to the restricted-use items is subject to approval by IEA Amsterdam. The response data for all items used in the assessment, however, are public and freely available in the data files. The item release policy is described in the Item Release Plan.