The reliability of a test of mental imagery is to be assessed. The test consists of 30 items. Each item requires the participant to form an image of some verbally described scene and then to rate the image for "clarity" on a ten-point scale. The test is given to 100 undergraduates. For the purposes of scoring, the 30 items are randomly divided into two sets of 15, and a mean score for each set is computed for each participant.