Revision for the Epreuve de Performance Cognitive (EPC)

The Epreuve de Performance Cognitive (EPC), a title that could be translated by Cognitive Performance Examination, is a nonverbal, sequential reasoning test aiming at assessing one's problem solving ability in both timed and liberally timed conditions. The EPC is suitable for persons of average ability as well as for gifted adults thanks to items of very high difficulty. The EPC is published by the ECPA in France. Availability is restricted to graduated psychologists.

During the last 2 days I've worked on the data collected from 1,764 test takers with the goal of revising the EPC. Like I did for the revision of the CCAT, I've added to the scoring process of the test a requirement for stopping after 5 consecutive misses by the examinee. A fully computerized version should be prepared very soon.

Psychometric properties weren't altered by this new rule. The reliability of the scores yielded by the EPC was observed to be .94 as estimated with the Spearman-Brown corrected Split-Half formula in the entire sample. The Cronbach's alpha was also very satisfactory at .92. The multidimensional scaling analysis confirmed the existence of a continuum in items from the easiest to the hardest. As shown in Figure 1, the two-dimensional solution appeared in a typical horsehoe shape (Stress = .14; RSQ = .92).

Figure 1. Two-dimensional scaling: a typical horseshoe shape that shows the continuum in items of the revised EPC. An inappropriate set of items would have produced a cloud figure rather than a horseshoe. Inadequacy values supported the two-dimensional solution, with a Stress of .14 and a RSQ of .92. (N = 1,764)

A principal components factor analysis performed thanks to 95 participants who reported recentered Scholastic Assessment Test (SAT-I) scores resulted in a first unrotated factor loading of .83 for the EPC. The Math reasoning scale of the SAT-I was saturated at .82, and the Verbal reasoning part at .75.

Correlations with other measures were sufficiently high. The EPC raw scores were seen to correlate at .82 with the raw scores on the Raven's Advanced Progressive Matrices (APM) in 134 subjects and at .81 with the raw scores on the Cattell's Culture-Fair Intelligence Test-3A (CFIT) in a sample of 156 observations.

Furthermore, raw scores on the EPC and FSIQ on the WAIS correlated at .85 in a highly selective sample of 23 adults with an average FSIQ of 131.70 (SD=24.35).

I've an important amount of remaining data that could be analyzed. Anyway, I've written to the test publisher to know if this new version of the EPC, as I humbly think, is interesting for another publication.