The Delis–Kaplan Executive Function System is a neuropsychological test used to measure a variety of verbal and nonverbal executive functions for both children and adults. This assessment was developed over the span of a decade by Dean Delis, Edith Kaplan, and Joel Kramer, and it was published in 2001. The D-KEFS comprises nine tests that were designed to stand alone. Therefore, there are no aggregate measures or composite scores for an examinee's performance. A vast majority of these tests are modified, pre-existing measures ; however, some of these measures are new indices of executive functions.
Nine tests
This measure consists of the following subtests:
The Trail Making Test measures flexibility of thinking on a visual-motor sequencing task
The Verbal Fluency Test measures letter fluency, category fluency, and category switching
The Design Fluency Test measures one's initiation of problem-solving behavior, fluency in generating visual patterns, creativity in drawing new designs, simultaneous processing in drawing the designs while observing the rules and restrictions of the task, and inhibiting previously drawn responses
The Color-Word Interference Test measures ability to inhibit a dominant and automatic verbal response
The Sorting Test measures concept-formation skills, modality-specific problem-solving skills, and the ability to explain sorting concepts abstractly
The Twenty Questions Test measures the ability to categorize, formulate abstract, yes/no questions, and incorporate the examiner's feedback to formulate more efficient yes/no questions
The Word Context Test measures verbal modality, deductive reasoning, integration of multiple bits of information, hypothesis testing, and flexibility of thinking
The Tower Test measures spatial planning, rule learning, inhibition of impulsive and perseverative responding, and the ability to establish and maintain instructional set
The Proverb Test measures one's ability to form novel, verbal abstractions
These 9 subtests generate 16 main achievement scores and hundreds of optional error, contrast, accuracy, and time-interval scores. As such, use of the computerized scoring assistant makes scoring the measure less time consuming. This assessment was normed with a representative sample. The D-KEFS has been criticized because only 17% of the reliability values published in the D-KEFS manual are above a 0.80 value. However, this may not pose serious concern due to the challenges of measuring executive functions. The D-KEFS offers a comprehensive portrayal of individual's EF skills, and the complexity of these tasks make them sensitive to the detection of even mild brain damage. In 2009, an abbreviated form of the D-KEFS was included in the Advanced Clinical Solutions for the WAIS-IV and WMS-IV. This abbreviated form of the D-KEFS consists of two subtests: the Trail Making test and the Verbal Fluency test. Using the ACS software, examiners can compare performance on these two subtests with performance on the WAIS-IV and WMS-IV, which allows for a more integrated assessment of functioning. In 2011, Crawford et al. made available free computer software that allows the assessor to calculate important supplementary values. These values help identify whether the assessee's overall pattern of performance on the D-KEFS deviates markedly from the normal population. Further, these values aid the assessor in identifying spuriously low scores that are due to inflated type one error rates when multiple scores are generated within the same tool.
