Studies have examined the multivariate effects of personality and intelligence on EI and also attempted to correct estimates for measurement error. For example, a study by Schulte, Ree, Carretta (2004), showed that general intelligence (measured with the Wonderlic Personnel Test), agreeableness (measured by the NEO-PI), as well as gender could reliably be used to predict the measure of EI ability. They gave a multiple correlation (R) of .81 with the MSCEIT (perfect prediction would be 1). This result has been replicated by Fiori and Antonakis (2011),; they found a multiple R of .76 using Cattell's "Culture Fair" intelligence test and the Big Five Inventory (BFI); significant covariates were intelligence (standardized beta = .39), agreeableness (standardized beta = .54), and openness (standardized beta = .46). Antonakis and Dietz (2011a), who investigated the Ability Emotional Intelligence Measure found similar results (Multiple R = .69), with significant predictors being intelligence, standardized beta = .69 (using the Swaps Test and a Wechsler scales subtest, the 40-item General Knowledge Task) and empathy, standardized beta = .26 (using the Questionnaire Measure of Empathic Tendency). Antonakis and Dietz (2011b) also show how including or excluding important controls variables can fundamentally change results.