摘要:Thinking skills are essential to achieve sustainable social development. Nonetheless, there is no specific instrument that assesses all of these skills as a whole. The present study aimed to design and validate a scale to assess complex thinking skills in adult people. A scale of 22 items assessing the following aspects: analysis and problem solving, critical analysis, metacognition, systemic analysis, and creativity, in five levels, was created. This scale was validated in 626 university students from Peru. In total, 16 experts in the field helped to determine the content validity of the scale (Aiken’s V value higher than 0.8). The confirmatory factor analysis allowed the evaluation of the structure of the five factors theoretically proposed and the goodness of fit indexes was satisfactory. An item was eliminated during the process and the scale resulted in 21 items. The composite reliability for the different factors was ranged between 0.794 and 0.867. The invariance between genders was also checked and the concurrent validity was proved. The study concludes that the content validity, construct validity, concurrent validity, and composite reliability levels of the COMPLEX-21 scale are appropriate.