The main objective of PIAAC is to produce high-quality cross-nationally comparable data on adult skills. The data are of particular public interest. They are used by scientists from a wide range of disciplines, and the results of the PIAAC study offer key players in policy-making and society a basis for policy interventions and strategy choices.
In order to achieve the objectives and to ensure that the data are of high quality, the survey must be conducted in a comparable and standardized way in all participating countries. To this end, the international PIAAC Consortium has defined extensive and detailed quality standards. The Consortium regularly monitors compliance with and the implementation of these international standards in the participating countries. In Germany, the internationally prescribed quality assurance standards are enhanced by further national measures.
The international PIAAC standards reflect the current state of research on survey methodology, and cover all areas of the survey life cycle:
- Quality assurance and quality control
- Study planning
- Sample design and sample selection
- Survey instruments
- Translation and adaptation of survey instruments
- IT hardware and configuration and integration with national survey management software
- Field management standards
- Interviewer training
- Data collection, fieldwork monitoring, and quality control of fieldwork
- Data management and verification
- Confidentiality and data security, data protection
- Weighting and variance estimation
- Quality indicators (e.g., response rate, sampling bias)
For the interpretation of the PIAAC results, it is crucial that the respondents are representative of the target population. In order to accurately assess the current situation in the participating countries and to be able to compare the results cross-nationally, it is crucial that as many of the selected persons as possible participate in the survey. According to international standards, a response rate of at least 70% should be achieved. Countries with lower response rates must utilize nonresponse bias analyses to prove that the realized sample is not – or is only marginally – biased.
Before data publication, the Technical Advisory Group will review each participating country's compliance with the quality assurance standards and determine the usability of its PIAAC data for analysis purposes (data adjudication). Key methodological aspects are the quality of the sample and the sampling procedure, coverage rate and sampling bias, data collection, and the quality of the instruments and the data. The results of this review will determine whether the data of the respective countries will be included in the international dataset and used in the international analyses.