The covariance index is a response validity scale created with the purpose of detecting intentional distortion in self-report measures. Based on evidence that strong response sets increase the covariance between responses, a method was developed to identify increased covariance at the individual level. Two studies were conducted to evaluate the validity of this new measure across laboratory and field settings. Results showed that individuals who scored higher on the covariance index in situations where strong response sets were present were those who had distorted responses the most and whose scores on personality measures had worse validity. In addition, the new validity scales improved identification of distorted responses beyond traditional social desirability scales.