Confirmation of Interrater Reliability of the Marley Differential Diagnostic Scoring System for the Bender-Gestalt Test

Abstract

The Bender-Gestalt test has been one of the most popular clinical instruments for the past four decades. Much controversy has surrounded the use of this test as a screening instrument for organicity (brain dysfunction). Marley's Differential Diagnostic Scoring System was recently developed to improve the validity of the test for detecting organicity. The original standardization of the system reported very high interrater reliability. To provide an independent assessment of interscorer reliability, three raters were trained in the system and separately rated 40 protocols. Kappa coefficients for the three raters ranged from .94 to .98. Substantial interscorer reliability was obtained, Mdn = 92.5% for specific scores with three scores attaining 100% agreement, although some values were lower. These results suggest that there is a strong empirical basis for the scoring system and encourage further refinement of the scoring system to reflect central nervous system dysfunction.