Interrater and Test–Retest Reliability of a Fixed Condition Design Fluency Test

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Abstract
Despite its potential as a unique neuropsychological test, the emergence of a psychometrically sound research foundation for Jones-Gotman and Milner's ( 1977 Jones-Gotman , M. & Milner , B. ( 1977 ). Design fluency: The invention of nonsense drawings after focal cortical lesions . Neuropsychologia , 15 , 653 – 674 . [Crossref], [PubMed], [Web of Science ®] [Google Scholar] ) Design Fluency Test (DFT) has been constrained by the lack of consistent administration and scoring practices and limited information about its reliability. Here we describe an approach to administering and scoring the fixed condition DFT that is modeled on Jones-Gotman and Milner's original method and that clarifies procedural ambiguities. Results include interrater and long-term test-retest reliability analyses using this approach. First, based on five raters who scored 50 DFT protocols, good to excellent intra-class correlation coefficients were obtained for all DFT scores. Second, in a broadly representative sample of 87 healthy adults who were tested twice over an average of 5½ years, the test–retest reliabilities for total and novel design scores ranged from good to excellent. This study demonstrates that the fixed condition DFT can be scored reliably using these procedures and that the reliability coefficients for DFT total and novel designs scores are comparable to those of other commonly used neuropsychological tests.