Respondent universe, sampling methods, norming phase procedures and propossed analysis - the NIH Toolbox for the Assessment of Neurological and Behavioral Function

The instruments in the NIH Toolbox are designed primarily for use in the general non-institutionalized population dwelling in the community, ages 3-85 years. Nationally representative reference values (norms) will be obtained using a probability sample of the US population, ages 3-85 years, stratified by age, gender, and Spanish language preference with at least 50-100 individuals in each of the major subgroups. A total of 4,400 individuals will participate in this NIH Toolbox norming study. Employing NIH Toolbox measures and additional tests and questionnaires, testing will take between 2.5 and 3 hours to complete for adults and older children, 1.5 to 2.5 hours for young children. Follow-up testing will be conducted on subsamples at 1 week and 3 months. State of the art methods will be used to maximize response rates and deal with non-response. Sample weights will be developed to allow accurate national estimates, while accounting for the accrual methods. Summary tables will provide norms within age, gender and language subgroups. Follow-up subsamples will allow an assessment of reliability and practice effects for the instruments. Results from the NIH Toolbox will provide a national resource of normed assessment instruments for use by investigators in future research.