Data Analysis and Reporting

Data analysis

Data collected in international large-scale assessments of educational achievement originate from complex unit- and item-sample designs. The hierarchical structure of education systems, and the complex structure of educational processes require sound knowledge of statistical methods suitable for analyzing and interpreting the data obtained from these assessments. The international context of international comparative research means that cross-country comparability must be established to generate reliable results.

Our data analysis services include:

  • Scaling of questionnaire and achievement test data, using, for example, Rasch or IRT scaling
  • Evaluating test consistency, the psychometric quality of the test items, and measurement invariance
  • Weighting of data, including nonresponse adjustment and scaling of weights  
  • Variance estimation, using, for example, jackknife or balanced repeated replication
  • Univariate and multivariate analysis, including multilevel analysis and structural equation modeling 
  • Development of simple descriptive and inferential statistics, for example, estimation of means, percentiles, benchmarks, correlation and regression coefficients, and the standard errors of these estimators.


The IEA has a wealth of experience in interpreting and reporting the results of its large-scale studies for diverse audiences, such as researchers, practitioners, policymakers, and the media. Careful consideration not only of the types of information most useful to these various groups but also of the best way of presenting that information to each one ensures effective dissemination and use of study findings.

Our services relating to reporting and disseminating study findings include:

  • Identifying the audiences interested in the study findings
  • Identifying which types of information each of these audiences is most likely to be interested in
  • Producing publications, both print and electronic, and ranging from press releases to full reports.

For further information about our data analysis and reporting services, please contact:

Dr Sabine Meinck   +49 40 48500 750 – randa [at]