In the context of a research protocol, this is done by assigning values to objects. If investigators are interested in developing a research design for an intervention that modified pain, for example, they need an a priori definition of pain. If we consider an outcome as simple as the measurement of the symptom of pain, for example, we soon realize that it is difficult to describe “pain” using the categories or numbers that are essential for statistical analysis required in research.

Most of these outcomes are actually very complex constructs, made up of many different components. This approach is simple for objective measures such as height and age but becomes much more complex when we try to measure health-related clinical outcomes that impact patients. Measurement is the process of systematically assigning numbers or words to physical and behavioral characteristics so that they can be defined, quantified, and differentiated. To differentiate between different types of measurements and to create the appropriate research designs using these concepts.To describe sources of variation in measurements.To explain the different components of validity (face, content, construct, and criterion validity) in the context of measurements.To explain the terms validity, reliability, and responsiveness and to be able to describe these properties for a given measure.

To explain types of variables and scaling.

To explain the importance of measurement properties to health outcomes research.

Measurements: Validity, Reliability, and ResponsivenessĪlexandra M.

Reliability and validity in research