Purpose
A comparison-adjusted funnel plot adapts small-study effect visualization to a network where studies belong to different direct comparisons. The goal is to inspect whether small-study patterns remain after accounting for comparison structure.
Coventra generates this plot from the netmeta object when the NMA small-study-effects module is requested and the selected network model supports plotting.
Ordering and direction
The comparison-adjusted funnel depends on treatment ordering and effect direction. Coventra can use ranking order when rankings are available; otherwise the package default order may be used.
Reviewers must verify whether lower or higher values are beneficial and whether the plotted direction matches the manuscript interpretation.
Limitations
- Sparse networks may not provide meaningful visual evidence.
- Star-shaped networks have limited information about comparison-specific asymmetry.
- High heterogeneity, intransitivity, or inconsistent outcome definitions can mimic small-study patterns.
- A generated plot is a screening aid, not proof of publication bias.
Reporting checklist
- Report that the funnel plot was comparison-adjusted.
- Report ordering and direction of benefit.
- State when the plot was unavailable or uninformative because the network was sparse.
- Interpret alongside direct evidence, transitivity, and inconsistency diagnostics.