Inter-Rater Reliability of the Raphael Projective System (RPS) of Scoring Projective Drawings

Abstract

Purpose: The current study was conducted to examine the inter-rater reliability of the Raphael Projective System (RPS), a standardized system for the administration, scoring, and interpretation projective drawings, including the Bender Gestalt Test, House-Tree-Person drawing test, Kinetic Family Drawing test, Draw a Person Test and Free Drawing test. In anticipation of completion of the comprehensive manual of the RPS, the authors examined the inter-rater reliability of raters who were trained on scoring House, Tree, and Person drawings. Methods: Three of the authors refined the scoring system and reached consensus on scoring for 30 projective drawing test protocols (ten House drawings, ten Tree drawings, and ten Person drawings), which they had independently scored. Five graduate clinical psychology doctoral students were trained on the system and independently scored the same 30 drawings scored by the authors. The percentages of agreement between the students’ and the authors’ scoring were calculated. Results: The average percentages of agreement between the student raters and the author’s were as follows: 90.90% for House drawings, 86.48% for Tree drawings, and 85.43% for Person drawings. Discussion: The findings suggest strong inter-rater reliability for the RPS, even for novice raters with minimal instruction on the system. The results are similar in strength to previous studies examining the reliability of projective drawing scoring systems. Key Words: projective drawings, House-Tree-Person, Person Drawings, Free Drawings, Kinetic Family Drawing, inter-rater reliability