Identifying scale and person response validity of a new assessment of driving ability

The purpose of this study was to evaluate evidence on the validity of a newly developed assessment tool, P-Drive (Performance Analysis of Driving Ability) intended to measure driving ability in a simulator. P-Drive was made available to a sample of 31 brain-damaged participants. P-Drive consists of 21 items relating to observable driving actions, each of which is scored on a 4-point criterion-referenced rating scale. A Rasch measurement model was used to evaluate whether P-Drive was a valid tool. The results indicated that P-Drive represented one single construct. All the items showed acceptable goodness-of-fit, indicating overall internal scale validity. The hierarchical order of the items in P-Drive was in agreement with the theories concerning driving ability after acquired brain injury, providing further evidence of validity. The participants also demonstrated acceptable levels of goodness-of-fit, indicating person response validity. The study indicates that the results for different aspects of the va...