Evaluating an instrument to measure mental load and mental effort considering different sources of validity evidence

This study evaluates a 12-item instrument for subjective measurement of mental load (ML) and mental effort (ME) by analysing different sources of validity evidence. The findings of an expert judgement (N = 8) provide evidence based on test content that the formulation of the items corresponds to the meaning of ML and ME. An empirical study was conducted in which secondary school students (N = 602) worked on multiple choice (mc)-tasks and...