Free Tools › Meta-Regression Bubble Plot

Meta-Regression Bubble Plot Generator

Fit a random-effects meta-regression and plot each study's effect size against a moderator, with bubbles sized by study weight and the fitted line with its confidence band.

FreeNo account neededYour data stays in your browser

Your dataColumns: study, effect size, standard error (or variance) and one or more numeric moderators.
20304050-1.5-1-0.500.5latitudelogRR

Mixed-effects meta-regression (REML, 13 studies)

Slope-0.0291 (95% CI -0.0432 to -0.0150)z = -4.04, p < 0.001
Intercept0.2515 (SE 0.2491)
Residual τ²0.0763I² = 68.4% residual heterogeneity
Test for residual heterogeneityQE(11) = 30.73, p = 0.001
Variance explained (R²)75.6%Proportional reduction in τ²

Bubble area reflects each study's weight; the shaded band is the 95% confidence interval for the regression line. Results match metafor's rma(..., mods = ~ x, method = "REML"). Associations across studies are observational and can be confounded.

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How to Use the Meta-Regression Bubble Plot

  1. 1

    Paste your studies

    Copy the columns from Excel or Google Sheets, with names in the first row, or load the example.

  2. 2

    Read the results

    Estimates, tests and the figure update instantly in your browser.

  3. 3

    Export

    Download the figure (SVG or PNG) and copy a results sentence.

Reading a meta-regression bubble plot

Each bubble is one study; larger bubbles carry more weight in the analysis. The line shows how the expected effect changes with the moderator, and the shaded band is its 95% confidence interval.

The test of the moderator (QM) asks whether the slope differs from zero. R² estimates the share of between-study variance explained. Meta-regression findings are observational: they show associations across studies, not causal effects.

How it is calculated

Sources

Meta-Regression Bubble Plot: FAQ

Why are ratio measures on a log scale?

Odds ratios and risk ratios are analysed as logarithms so that effects are symmetrical around no effect. The axis can show the back-transformed values.

Can meta-regression prove a dose-response effect?

No. Across-study relationships can be confounded by other study characteristics (ecological bias).

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