title: Measurement in physical therapy. On the rules for assigning numerals to observations.
abstract: This paper discusses certain issues of theory, concept, definition, and method in measurement that are of concern to physical therapy. The topics discussed include the place of measurement in science, definitions of measurement, direct and indirect measurement, the logical requirements of measurement, scales of measurement, precision and accuracy, and reliability and validity. Comments pertinent to physical therapy are included in the discussion, and the issues are summarized by a look at the complex problems of using EMG for measurement of muscle activity.
mesh_terms: D004576:Electromyography; D026741:Physical Therapy Modalities; D012106:Research