Does choice of measure matter? Assessing the similarities and differences among self-control scales

Purpose: To assess the extent to which three well-validated measures of self-control are assessing the same construct. Methods: Two student samples (ns = 315 and 172) completed multiple self-control scales (the Grasmick et al. scale, Weinberger Adjustment Inventory-Restraint, and the Tangney et al. scale), as well as other personality traits, aggression, and offending scales. Results: The three scales correlated highly with one another (rs ranged from 0.65-0.69) and rank-order differences were uncommon (approximately 80% were within 1 standard deviation). However, each scale demonstrated somewhat different patterns in terms of their relationships with other personality indices, aggression, and offending. Conclusions: The Grasmick scale and Weinberger Adjustment Inventory were similar to one another in many (but not all) instances, and both were distinct from the Tangney scale. The three self-control scales used in this analysis have much in common, but they are not identical. Moreover, with the exception of the Tangney scale, the constructs assessed by the self-control scales are not synonymous with Conscientiousness or impulsivity. Care should be exercised in including these different self-control scales and similar constructs (e.g., impulsivity) within meta-analytic studies as effect sizes risk being misspecified.