The aim of this study was to determine the metric characteristics of the instrument for measuring the ability of decision making, compounded of the original Cognitive Reflection Test items and additionally constructed items. Considering that the original CRT does not have high enough reliability, the goal of the new measure was to increase that reliability with the condition that new items must remain measures of cognitive reflection. The criterion validity of the new instrument was analyzed by exploring to what extent the new instrument can predict the outcomes of real life decisions. Data was collected from 253 students who differed in age, faculty and year of faculty. The new CRT has shown higher reliability (.86 Cronbach alpha). Good construct validity was shown through high positive correlation with the original short CRT version and medium high positive correlation with Test of Syllogisms. Those correlations show that these instruments measure same construct. A moderately positive correlation was measured between the new CRT and the intelligence test ICAR (International Cognitive Ability Resource) which did not differ significantly from the correlation of the CRT with the Test of Syllogisms. This result opens up a possibility for more detailed exploration of the relationship between intelligence and cognitive reflection. On the other hand, the results of the study do not support the prognostic validity of the new CRT for the results on the Decision Outcome Inventory.