Although single items can save time and burden in psychology research, concerns about their reliability have made the use of multiple-item measures the default standard practice. Although single items cannot demonstrate internal reliability, their criterion validity can be compared with multiple-item measures. Using ecological momentary assessment data, we evaluated repeated measures correlations and constructed multilevel cross-lagged models to assess concurrent and predictive validity of single- and multiple-item measures. Correlations between the single- and multiple-item measures ranged from .24 to .61. In 27 of 29 unique single-item predictor models, single items demonstrated significant predictive validity, and in one of eight sets of comparisons, a single-item predictor exhibited a larger effect size than its multiple-item counterpart. Although multiple-item measures generally performed better than single items, the added benefit of multiple items was modest in most cases. The present data provide support for the use of single-item measures in intensive longitudinal designs.

Mental health problems are common for persons with neurological disorders (PWNDs) and their caregivers (CGs) but often are not adequately treated. Despite this growing need, the training of clinical psychologists typically does not include coursework or practicum experience working with these populations. To address this, a team of faculty, supervisors, and doctoral students in UC Berkeley's Clinical Science program undertook a year-long process that consisted of building a training curriculum that integrated coursework and consultation with visiting experts; providing supervised practicum training with PWNDs and CGs and evaluating training and clinical outcomes. We hoped to prepare students to train other mental health professionals to work with these populations in the future. In this article, we describe the Specialty Clinic with special attention given to the training provided, challenges faced and solutions found, clinic operations and logistics, and lessons learned. We also review key clinical issues and report key indicators of client outcomes. Finally, we evaluate the success of the Specialty Clinic and offer recommendations for others interested in providing these kinds of much needed training and clinical services in this important area.