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Sensitivity of treatment recommendations to bias in NMA (Phillippo threshold framework)

Methodpeer-reviewed✓ Source-grounded

This method helps assess how strong the evidence is in a network meta-analysis by showing how much bias would need to exist to change the recommended treatment. It calculates thresholds that indicate how sensitive a decision is to potential biases in the data.

At a glance

Use when

Conducting sensitivity analysis in network meta-analysis to assess decision robustness; when risk of bias may influence treatment rankings; to support decision-making under uncertainty

Avoid when

The NMA model structure or covariance matrix is unavailable; when bias is expected to act non-additively or through complex mechanisms not captured by simple adjustments

Inputs

Network meta-analysis data, including treatment effects and variance-covariance structure; optionally, risk of bias assessments for individual studies

Outputs

Bias adjustment thresholds indicating the minimal changes needed to alter treatment recommendations; sensitivity measures for individual studies or treatment contrasts

How it works

The method computes bias adjustment thresholds using efficient matrix operations to determine the minimal changes in study data that would alter treatment recommendations in fixed or random-effects network meta-analysis models. It supports exploration of bias impacts at the level of individual studies or aggregate treatment contrasts. For complex models with multiple data types, an approximation to the hypothetical aggregate likelihood is used. Implemented in an R package.

HTA domains
Clinical Effectiveness, Costs & Economic Evaluation
Assumptions
The impact of bias can be approximated by adjusting study-level effect estimates; the NMA model is correctly specified; the decision is based on relative treatment effects
Strengths
Provides quantitative, interpretable thresholds for decision robustness; applicable to both fixed and random-effects models; handles complex NMAs via likelihood approximation; enables targeted sensitivity analysis
Limitations
Relies on approximations for complex data types; assumes bias acts additively on effect estimates; does not model bias mechanisms directly; requires access to NMA model structure and covariance matrix
Also known as
Phillippo threshold framework, Bias adjustment thresholds in NMA

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