Ankylosing spondylitis antirheumatic drug trials: Effects of a standardized instructional videotape on the reliability of observer-dependent outcome measures

Aims: A study was designed to assess the effects of a standardized instructional videotape on reducing interobserver variability for several commonly used observer-dependent outcome measures. Methods: During a single day, six rheumatologists independently examined six patients with ankylosing spondylitis (AS) in a predetermined order using a Latin square design, before and after viewing a standardized videotape demonstrating 14 examination techniques. Reliability coefficients were calculated based on the variance components of the analysis of variance (ANOVA) table. Results: Prestandardization reliability coefficients wer