Cognition-UPSA score relationships: a further analysis of Silverstein et al. (2010) data and some caveats

Silverstein et al. (2010) reported correlations between scores on the UCSD Performance-Based Skills Assessment (UPSA) and scores on two cognitive test batteries (MATRICS Consensus Cognitive Battery and IntegNeuro) that were lower than those reported in past studies. The large sample size of that 4-site study (155 patients with schizophrenia) allowed for further analyses of the data to explore the reasons for the discrepancy. We examined the data from Silverstein et al. (2010) to determine if the correlation values obtained were affected by UPSA scoring method, site differences, patient level of functioning, range restriction, missing data, and/or whether data from the first or second administration of each cognitive test battery were used. Results indicate that the overall lower cognition-UPSA correlations were a function of a single site with unusually low correlations. However, the low correlations at this site were not a function of any of the potential causes we examined. Correlations at the other sites were close to or within the range reported in past studies. Interestingly, the correlation between IntegNeuro and UPSA composite scores was higher at Time 2, suggesting that cognition-UPSA correlations are affected by familiarity with the computerized test format.