The main aim of this study was to assess the reliability and validity of a food frequency questionnaire with 23 food groups (I-FFQ) among a sample of 9–11-year-old children from three different ...

The regression of lung function change on the initial lung function level is biased when the initial level is measured with random error. Several methods have been ...

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

The study was conducted at the rehabilitation clinic "RehaClinic" (locations Bad Zurzach and Braunwald, Switzerland), which is attended by severely disabled patients suffering from persistent ...