Instrumentation

Instrumentation refers to the tools or means by which investigators attempt to measure variables or items of interest in the data-collection process. It is related not only to instrument design, selection, construction, and assessment, but also the to conditions under which the designated instruments are administered—the instrument is the device used by investigators for collecting data. In addition, during the process of data collection, investigators might fail to recognize that changes in the calibration of the measuring instrument(s) can lead to biased results. Therefore, instrumentation is also a specific term with respect to a threat to internal validity in research. This entry discusses instrumentation in relation to the data-collection process, internal validity, and research designs.