Development of an Optimally Reliable Short Form for Judgment of Line Orientation

Abstract

Standard and short forms of Judgment of Line Orientation-Form V (JLO; Benton, Sivan, Hamsher, Varney, & Spreen, 1994) were examined for internal consistency (coefficient alpha) in a diagnostically mixed neuropsychiatric sample (N = 230). Equivalence of internally consistent short forms was assessed by correlating them with the full form of the test. Internal consistency for the full 30-item form of JLO (alpha = .84) approximated the optimal level of .80 (Nunnally, 1978). Two 20-item short forms of JLO (items V1-V20 and items V11-V30) also reached comparable alpha levels (alpha = .75 and .80, respectively). These two JLO short forms correlated .90 and .97, respectively, with the full 30-item form. We recommend the JLO short form based on items V11-V30 for clinical use in situations in which employment of the full form may not be advisable and offer a short-to-long-form conversion table for clinical use.