Background: Self-report questionnaires play an important role as outcome measures in shoulder research. Having an estimate of the measurement error of these ...

Self-administered food frequency questionnaires (FFQs) are the most economical method to estimate dietary intake of foods or nutrients in large-scale epidemiological studies. However, FFQs are prone ...

Survey research is an important form of scientific inquiry1 that merits rigorous design and analysis.2 The aim of a survey is to gather reliable and unbiased data from a representative sample of ...

Despite extensive use over 40 years, physical activity questionnaires still show limited reliability and validity. Measurements have value in indicating conditions where an increase in physical ...