Introduction to instrument development for postanesthesia studies

An important aspect of any research project is the selection of the instrument for which a "fit" exists between what is to be studied and the subjects. Physiological instruments are developed to objectively measure specific variables, such as temperature. Psychological instruments are usually developed to subjectively measure specific variables; however, there may not be a fit if the researcher used a paper-and-pencil instrument developed to measure anxiety in psychiatric patients to measure anxiety in the sedated, postanesthesia patient. An introduction to instrument development is presented including defining instruments, deciding what phenomena to measure and how to measure them, locating existing instruments, deciding when to develop an instrument, and identifying implications that arise from the use of inappropriate instruments.