Cognitive Load Scale (CLS)

The Cognitive Load Scale (CLS), developed by Fred Paas in 1992 and refined by Paas and colleagues in subsequent years, is a brief, single-item or multi-item self-report instrument for assessing the cognitive load (mental effort) imposed by a learning or task environment. Originating in cognitive load theory research, the CLS has become a fundamental measurement tool in educational psychology, instructional design, and human factors, used to evaluate how instructional materials, interface designs, or training methods affect learner or operator mental burden.