ABSTRACT
The internal consistency of measurement tools is often characterized using coefficient alpha, an indicator of how well the items fit together or correlate with one another. Once a measure is in its final form, research is necessary to determine whether it is accurate and has value for its intended purpose. Such studies serve school psychology by helping practitioners determine whether a measure can be used with a certain student or population within a certain setting. This work shares much in common with the work done to develop a measure. Reliability refers to the consistency of a score yielded by a measurement tool. Reliability evidence is a prerequisite to a validity argument in that before a score can be shown to reflect a specific construct, it must be shown to be consistent under consistent conditions. Internal consistency estimates can be convenient to obtain because they are calculated on a single set of scores.
