What the risk of bias figure shows
A systematic review does not only say what each study found: it says how far that can be trusted. The risk-of-bias assessment is that judgement, domain by domain, and the figure is how it is shown at a glance. Cochrane requires it in its reviews and most journals expect it in any review with a meta-analysis.
There are two figures. The traffic light plot has one row per study and one column per domain, with a coloured dot at each crossing. The summary plot stacks, for each domain, the percentage of studies at each level. The first says where each study is weak; the second, where the body of evidence is.
Which instrument you need
The instrument follows the design of the included studies, not the review question. If you mix designs, make one figure per instrument.
- RoB 2. Randomized controlled trials. Five domains and an overall judgement: low risk, some concerns, high risk.
- ROBINS-I. Non-randomized studies of interventions. Seven domains; the levels are low, moderate, serious and critical.
- ROBINS-E. Non-randomized studies of exposures. Seven domains; the levels are low, some concerns, high and very high.
- QUADAS-2. Diagnostic accuracy studies. Four risk-of-bias domains and three applicability concerns, no overall judgement.
- Newcastle-Ottawa. Cohort and case-control studies. Three sections that award stars; the figure maps them to good, fair and poor quality.
- JBI. Checklist for analytical cross-sectional studies: yes, no, unclear or not applicable on each of its eight items.
How to read the figure
Every dot is a judgement. Green with “+” is low risk; yellow with “–”, some concerns or moderate; red with “×”, high or serious risk; dark red with “!”, critical or very high; grey with “?”, no information. The symbol sits inside the dot so the figure survives black-and-white printing and colour blindness.
Columns are named D1, D2… and the key under the figure says which domain each one is, in the instrument’s exact words. The last column, when the instrument defines one, is the study’s overall judgement.
In the summary plot every bar adds up to 100 % of the studies. With weighting on, each study counts according to its weight in the meta-analysis, and the bar says how much of the evidence is at risk rather than how many papers.
How to fill it in
- Choose the instrument and, if the journal asks, the language of the figure.
- Add one row per study or paste the table from your spreadsheet. The downloadable template has robvis’s columns: Study, D1…Dn, Overall and Weight.
- Mark the level of each domain. The cell takes the colour of the judgement and the figure redraws at once.
- Fill in the overall judgement by hand or with the button that applies the instrument’s rule.
- Download the traffic light plot, the summary plot or both.
Exporting for a journal
Use PDF or SVG when the journal asks for vector artwork; both keep the text sharp at any size. Use PNG at 3x when the submission system demands a high-resolution bitmap. The CSV keeps the table with robvis’s columns, to load it here again or open it in R.
What you download carries a revisia mark at the bottom right, outside the figure. Sign in to your revisia account with a verified email and the figure comes out clean, in the preview and in every format. The account is free.
Frequently asked questions
Which instrument should I use for which study design?
RoB 2 for randomized controlled trials. ROBINS-I for non-randomized studies of interventions (treated cohorts, before-after designs). ROBINS-E for non-randomized studies of exposures (environmental, occupational, dietary). QUADAS-2 for diagnostic accuracy studies. Newcastle-Ottawa or the JBI checklist for cohort, case-control and cross-sectional studies. If your instrument is not listed, the custom instrument lets you name 2 to 12 domains.
What do the colours and symbols mean?
Green with “+” is low risk (or “yes” in a checklist). Yellow with “–” is some concerns, moderate or unclear. Red with “×” is high or serious risk. Dark red with “!” is critical or very high, a level only ROBINS-I and ROBINS-E have. Grey with “?” is no information. The symbol sits inside the dot so the figure still reads in black and white and for colour-blind readers.
Is this the same figure robvis makes?
It is the same kind of figure: the traffic light plot and the summary plot made standard by the robvis package of McGuinness and Higgins. The arrangement, the levels and the data template follow robvis so you can move your data either way. The colours are revisia’s, and every dot carries a symbol, which robvis offers too.
How do I cite the figure and the instruments?
Cite the instrument you used: RoB 2 is Sterne JAC et al. BMJ 2019;366:l4898; ROBINS-I is Sterne JAC et al. BMJ 2016;355:i4919; ROBINS-E is Higgins JPT et al. Environ Int 2024;186:108602; QUADAS-2 is Whiting PF et al. Ann Intern Med 2011;155:529-36; the Newcastle-Ottawa Scale is Wells GA et al. (Ottawa Hospital Research Institute). To acknowledge the figure type, cite robvis: McGuinness LA, Higgins JPT. Res Synth Methods 2021;12:55-61. This tool itself needs no citation.
Does my data leave the browser?
No. The table, the figure and every file are generated on your device. The draft is kept in your browser’s local storage, and the share link carries the table inside the address itself, after the hash, which browsers never send to any server.
Why is there a watermark and how does it go away?
What you download carries a revisia mark at the bottom right, outside the figure. Sign in to your revisia account with a verified email and the figure comes out clean, in the preview and in every format. The account is free and there is no paid version of this tool.
What about the overall judgement in QUADAS-2 and JBI?
QUADAS-2 defines no overall judgement: it asks for each domain to be reported separately, and the figure does that, with the three applicability questions in a block of their own. The JBI checklist ends in a decision (include, exclude, seek further information), not a risk level, so it has no overall column either. In RoB 2, ROBINS-I and ROBINS-E the “Fill in the overall judgement” button applies the instrument’s rule, the worst domain decides, and you can then change it. Bear in mind that RoB 2 and ROBINS-E allow several domains at “some concerns” to justify an overall judgement of high: that call is yours, the button does not make it.
How do Newcastle-Ottawa stars come in?
The figure uses the three AHRQ quality bands (good, fair, poor) because a star count has no colour of its own. Pick the band in each cell, or paste the star count of each section: selection 3–4 good, 2 fair, 0–1 poor; comparability 1–2 good, 0 poor; outcome or exposure 2–3 good, 0–1 poor. Only selection can be “fair”: under the AHRQ standard a study is good with 3–4 stars in selection, 1–2 in comparability and 2–3 in outcome; fair with 2 in selection and the same in the other two; and poor with 0–1 in selection, 0 in comparability or 0–1 in outcome. The conversion happens as you paste.