At present, there are many studies that collect information on aspects of neurologic and behavioral function (cognition, sensation, movement, emotion), but with little uniformity among the measures used to capture these constructs. Further, available measures are generally expensive, normed on homogenous nondiverse populations, not easily administered, do not cover the lifespan (or have easily linked pediatric and adult counterparts for the purposes of longitudinal comparison), and not based on the current thinking in the neuroscience community. There is also a paucity of measurement tools to gauge normal children in the motor and sensation domain areas, and many of these measures rely heavily on proxy reporting. Investigators have expressed the need for brief assessment tools that could address these issues and be used as a form of "common currency" across diverse study designs and populations. This ability to assess functionality along a common metric and "crosswalk" across measures is essential to the process of being able to pool data, which is often necessary when a large and diverse sample is needed. When individual studies employ unique assessment batteries, comparisons between studies and combining data from multiple studies can be problematic. The contract for the NIH Toolbox for the Assessment of Neurological and Behavioral Function (www.nihtoolbox.org) was initiated by the NIH Blueprint for Neuroscience Research (www.neuroscienceblueprint.nih.gov) to develop a set of state-of-the-art measurement tools to enhance collection of data in large cohort studies and to advance the biomedical research enterprise.