ICILS 2018 Data

Data analysis
  • Item response theory (IRT) scaling was used to summarize student results assessment using plausible values methodology to obtain proficiency scores for all students.
  • All statistics were computed using sampling weights.
  • Estimation of standard errors for significance testing was computed by making use of:
    • Replication methods (jackknife repeated replication, jackknife zone, and replicate weights) to estimate sampling variance, and
    • Five plausible values for estimating measurement variance.
  • General note: ICILS data were designed for group-level reporting, and students’ scale scores in the database are not intended to report performance of individual students or very small groups, i.e., fewer than 50 individuals (students or teachers).
Secondary analysis

For doing secondary analyses, data can be analyzed with the IEA IDB Analyzer. This tool takes into account the characteristics of the sampling and assessment design, implements the corresponding replication method, and makes use of existing plausible values to produce accurate statistical results.

Types of data files

The data files include the student responses to the computer and information literacy (CIL) and computational thinking (CT) achievement items and the responses to the student, teacher, school, and ICT coordinator questionnaires.

  • Student data files
  • School data files
  • Teacher data files

Within each file type, the set of variables are defined homogeneously across all countries.

Format(s) of data files
Item release policy

Responses to all items used in the assessment were included in the database. To protect the confidentiality of the study respondents, ICILS 2018 applied certain disclosure avoidance measures at the international level, such as scrambling of identification variables and jackknife zone information, suppression of highly identifying respondents.

Therefore, the ICILS 2018 international database is available in two versions: a public use file (PUF) and a restricted use file (RUF):

  • A number of variables were removed or categorized from PUFs to minimize the risk of disclosing confidential information. However, the same scientific results can be obtained repeating the analysis using these files.
  • The RUFs is an extended version for scientific use.

While the use of the actual released items is subject to approval by the IEA Secretariat, the response data to all items used in the assessment is publicly available in the data files.