Analysis of Effectiveness
SECONDARY
The effectiveness of stratified blended physiotherapy compared with face-to-face physiotherapy for the primary and secondary clinical outcomes was estimated using linear mixed models. A 2-level structure was used comprising repeated measurements (level 1) nested within patients (level 2). The necessity of using additional levels in the random-effects model to control for the clustering of patients within physiotherapy practices and individual physiotherapists was checked using log-likelihood ratios [