Measuring change: A commentary on Keith et al. (2002)

A study by J. R. Keith et al. (2002) purported to find postoperative changes in attention in a sample of patients who underwent cardiopulmonary bypass surgery. Detecting differential patterns of neuropsychological change following treatment presents formidable methodological and statistical challenges. This commentary examines the findings of J. R. Keith et al. with regard to (a) the feasibility of randomizing research participants into treatment and control groups, (b) the handling of missing data, (c) the selection of statistical techniques to measure change, and (d) the measurement of differential neuropsychological deficit. Alternative strategies are discussed.