An evaluation of the effectiveness of a videotape programme on interobserver reliability in outcome assessment for ankylosing spondylitis

Aims. A study was designed to assess the effects of a standardized instructional videotape on training senior medical students to acceptable levels of reliability in performing several commonly used obsever dependent outcome measures in patients with ankylosing spondylitis (AS). Methods. During a single day, six third-year medical students independently examined five patients with AS in 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 were < 0.80 for three measures. Following standardization 12 reliability coefficients exceeded 0.80. For the majority of measures prestandardization reliability coefficients were high and no further improvement in reliability could be demonstrated. Conclusions. High levels of interobserver agreement were noted prior to viewing the instructional videotape. This may represent the success of undergraduate clinical skills training programmes, or it may be the result of having reviewed an illustrated instructional text just prior to the initial patient examinations. With the exception of chest excursion, high levels of prestandardization reliability, by necessity, precluded the demonstration of significant effects from viewing the videotape. Nevertheless, the data indicate that senior medical students are capable of reliably performing quantitative measurement in AS. Recent surveys in Canada and Australia, showing a general lack of quantitative clinical measurement in the longitudinal follow up of AS outpatients by rheumatologists, suggest that the lack of quantitation is not due to inability to reliably perform the measurements