Evaluation and research in physical therapy

The profession of physical therapy has a obligation to evaluate its many treatment and testing methods to ascertain their value, importance, and usefulness. Our evaluation of what we do must be based on measurement and research in physical therapy. The principles of measurement and research are discussed in some detail. The four scales of measurement, and the data they produce, are described. Test reliability and validity are discussed. Research is defined and its two principal forms, experimental and correlational, are discussed. The use of these principles in evaluating physical therapy treatment and testing methods is described by using clinical examples.