Trail Making Test: issues in normative data selection.

The Trail Making Test (TMT) is one of the most frequently administered neuropsychological instruments, having been used in the evaluation of cognitive dysfunction for over 50 years. Despite the measure's extensive clinical use and proliferation of research, no comprehensive review of the adult TMT normative literature is available. This report examines the available TMT normative reports and provides a summary of the sample characteristics. Significant variability between studies precludes the use of metanorms. Clinically, these findings indicate that biased results may be obtained if the most appropriate normative data set is not used and underscore the importance of identifying the normative comparison group that approximates the relevant patient characteristics. To assist the clinician, selected normative reports (based on certain exclusionary parameters) have been compiled for three nonclinical comparison groups: (a) an adolescent and young adult group (ages 15-24), (b) an adult group (ages 20-54), and (c) an older adult group (ages 55-85). Results are discussed in terms of the influence of moderator variables on TMT performance and other factors, such as procedural differences in administration, that may account for the significant variability between normative samples.