Principles of psychometrics applied to the evaluation of pain

Given the implicit subjectivity of pain, the building of evaluation tools that avoid the opinion of patient is difficult. Therefore, it seems indispensable to develop methods that consider their opinion and still were valid and reliable. The application of psychometric principles to development of instruments devoted to evaluate pain is compulsory to permit its use in the clinical setting. The present article reviews the most relevant concepts related with psychometric development, and outlines the main paradigms used to establish the usefulness of these instruments, as reliability, validity and factor analysis.