appendix i illustration to aid understanding of methodology

Appendix I Illustration to aid understanding of methodology

The following shows an illustration of a forest plot to supplement the methods in the text. Due to the large number of contrasts and models forest plots have not been used to display results in the main paper but an abbreviated plot is used here to show how the results in Figures 2/3 were obtained through meta-analysis. Examples of actual anchors/contrasts in each expert size class for the global QOL subscale are used in the following example. The mean differences and confidence intervals are not to scale and intended for illustration only.

Paper/Contrast number: Anchor: Contrast (A vs B)

2/1: Randomised treatment: 25mg vs 100mg13/1: Age: 60-64 vs 55-59776/3: Primary disease: Breast vs Colon

Subtotal (Trivial)*

Random effects mean difference ± 95% confidence interval

A better No diff B better

0

Average expert opinion

TrivialTrivialTrivial

776/2: Disease stage: III vs I496/3: Comorbidity: Comorbidities vs None20/1: Disease stage: Recurrence vs no recurrence

Subtotal (Small)*

SmallSmallSmall

169/3: Performance status: Deteriorated vs Improved169/4: Weight loss: >10% vs none261/4: Performance status: Karnofsky 40-60 vs 90-100

Subtotal (Medium)*

MediumMediumMedium

*These subtotals and 95% confidence intervals from the meta-analysis for Trivial, Small and Medium effects are displayed in the main paper; in Figure 2 for the mean difference outcome variable and in Figure 3 for the effect size outcome variable.

(Actual number of contrasts=39)

(Actual number of contrasts=97)

(Actual number of contrasts=54)

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