Reliability of psychometric tools

The article discusses two papers in the issue which focus on new developments in psychometric methods for the assessment of instruments. Leung and colleagues, highlight the need to address the reliability and validity of the data collected by psychometric tools, to avoid the two fundamental errors (systematic and non-systematic) causing inconsistencies in datasets. West and colleagues use the Family Impact of Pain Scale (FIPS) questionnaire on three domains for psychometric testing.