Risk-of-bias traffic light plot

Domain-level risk-of-bias table plot

MA
NMA
A grid of studies by risk-of-bias domains, with colored symbols for each judgment.
MANMAEstablished

Risk-of-bias traffic light plot example

RoB 2 judgments for nine example studies across five domains and overall: low risk (green plus), some concerns (yellow minus), high risk (red cross). Data: robvis::data_rob2.
Family
Risk of bias and reporting
Purpose
Report the risk-of-bias judgment for every study and domain.
Inputs
Domain-level and overall risk-of-bias judgments per study.
Software
R robvis::rob_traffic_light(); RevMan; the robvis web app

What it shows

Every systematic review with a meta-analysis reports its risk-of-bias assessment. The traffic light plot, standardized by the robvis package for tools such as RoB 2, ROBINS-I, and QUADAS-2, shows each study’s judgment in each domain and overall, with color and symbol so that it remains readable in grayscale.

How to read it

  • Rows: studies; columns: risk-of-bias domains and the overall judgment.
  • Symbols and colors: low risk, some concerns, high risk (and, for some tools, no information).
  • Footnote: domain definitions.

Interpretation

Studies 4 and 9 are at high risk of bias overall, driven by a single high-risk domain each (missing outcome data). Three studies (3, 6, and 7) have some concerns overall. Only studies 1, 2, 5, and 8 are judged low risk overall, although study 5 has high risk in two domains, an inconsistency worth checking against the tool’s algorithm.

Pitfalls

  • The plot reports judgments; it does not show how they affect the results. Pair it with a forest plot with risk-of-bias columns or sensitivity analyses.
  • Overall judgments must follow the tool’s algorithm; they are not averages of domains.
  • Colors alone fail for color-blind readers; keep the symbols.

Code

library(robvis)

# Example RoB 2 assessments shipped with robvis
data(data_rob2)
rob_traffic_light(data_rob2, tool = "ROB2", psize = 12)

References

  • McGuinness LA, Higgins JPT. Risk-of-bias VISualization (robvis): an R package and Shiny web app for visualizing risk-of-bias assessments. Res Synth Methods. 2021;12:55-61. doi:10.1002/jrsm.1411
  • Sterne JAC, Savović J, Page MJ, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898. doi:10.1136/bmj.l4898