THE VARIABLE RESPONDING SCALE FOR DETECTION OF RANDOM RESPONDING ON THE MULTIDIMENSIONAL PAIN INVENTORY

This study developed a scale for detecting random responding on the Mu ltidimensional Pain Inventory (MPI). Ninety-five undergraduates (deriv ation sample) completed the MPI randomly, as did 2 cross-validation sa mples, 34 chronic pain patients (pain) and 115 health care professiona ls (health care). Up to 71% of random profiles appeared valid. For com parison in validity scale development, a clinical MPI sample (N = 507) was split into derivation and cross-validation samples. Given that re sponses to similar items should be consistent in nonrandom protocols, 8 pairs of highly intercorrelated items were selected. Absolute differ ences between pairs were summed into a variable responding (VR) scale; scores were contrasted across clinical and random groups. On the basi s of derivation sample results, VR scale cut scores (from 12 to 17) we re tested and found to discriminate accurately (p < .001) between the cross-validation clinical and the healthcare and pain random respondin g samples. The potential clinical utility of the VR scale to identify random MPI protocols is supported.