GESIS Leibniz Institute for the Social Sciences: Go to homepage
Programme for the International
Assessment of Adult Competencies

International Adult Literacy Survey (IALS)

The PIAAC study based on two previous international studies with adults (16-65 years old): the International Adult Literacy Survey (IALS) and the Adult Literacy and Lifeskills Survey (ALL). The conceptual and methodological insights gained from IALS and ALL were used to expand and improve cognitive competence assessment of adults in the PIAAC stude, for example, in sampling, measurement, data acquisition, and data processing, as well as weighting and estimating. An overview of the three studies and the conceptual changes can be found in Thorn (2009) and for Germany in Maehler (2018) (2.34 MB).

The aim of the IALS study was to collect basic skills qualifications; defined as “Using printed and written information to function in society, to achieve one’s goals, and to develop one’s knowledge and potential.” (see Kirsch, Jugeblut und Campbell, 1992; Lehmann & Peek, 1996). In Germany the IALS study was conducted during autumn of 1994 and was led by Prof. Dr. Rainer Lehmann (Humboldt University Berlin).

ZA6847: International Adult Literacy Survey (IALS), Germany

Data collection period

 September 1994 - November 1994

Available since

 April 2020

Target population

16- to 65-year-old adults

Sample size



Background Questionnaire; paper-based assessment in the domain literacy (prose, document and quantitative literacy)

Main topics of Background Questionnaire General information about the household and respondents; educational attainment and participation in further education; labour-force status and employment; skill use at work and in daily life



Further documentation

Technical Report

Variable Report


Background Questionnaire (only in German)

Data access

PIAAC data via GESIS Data Catalogue (DBK)

(directly to the document:ZA6847_IALS_DataDistributionContract.pdf“)



GESIS – Leibniz Institute for the Social Sciences (2020). International Adult Literacy Survey (IALS) - Germany. Data file version 1.0.0 [ZA6847]. Cologne: GESIS Data Archive. doi: 10.4232/1.13515