One of the unique aspects of PIAAC is the adaptive design of the computer-based assessment within the domains of literacy and numeracy. The adaptive testing process means that respondents will be directed to a set of easier or more difficult items based on their answers to the ICT core and literacy/numeracy core questions (which are automatically scored as correct or incorrect).
The choice of assessment items for each participant mainly depends on an algorithm using a set of variables that includes: i) the participant's level of education, ii) the participant's status as a native or non-native language speaker; and iii) the participant's performance in the CBA Core (as well as their performance in the CBA Module as they advance through the assessment). For the problem-solving domain, there is no adaptive process.
The key advantage of an adaptive design is to provide a more accurate assessment of participants' abilities, while using a smaller number of assessment items than a traditional test design in which respondents must answer all questions included in the test, from easiest to most difficult.