help midas pubbiasalso see: midas

Title

midas pubbias -- Deeks funnel plot for publication bias in diagnostic meta-analysis

Syntax

midas pubbias
[if exp]
[in range]
[, options]

Plot elements
wgt weight study points by effective sample size (bubble plot)

nowgt display unweighted equal-size study points

regline overlay the weighted regression line

sumline add a vertical reference line at the summary log DOR

Styling
pointopts(scatter_options) marker options for the study scatter points

regopts(line_options) line options for the regression line

graph_options any twoway options

Inference
level(#) confidence level for the asymmetry test; default level(95)

Description

midas pubbias produces the Deeks et al. (2005) funnel plot for assessing
publication bias and small-study effects in a diagnostic accuracy meta-analysis.
It plots the log diagnostic odds ratio (log DOR) on the x-axis against 1/sqrt(ESS)
on the y-axis, where ESS = 4n1n2/(n1+n2) is the effective sample size. Smaller
studies appear higher in the plot. A funnel that is asymmetric (non-zero intercept
in the regression of log DOR on 1/sqrt(ESS)) suggests selective reporting.

The regression is run with ESS weights and reported with a formal test of the
intercept. A significant p-value (typically p < 0.10) is taken as evidence of
asymmetry. The command must follow a midas mle, midas qrsim,
midas mh, midas hmc, or midas inla estimation.

wgt and nowgt are mutually exclusive.

Options

wgt sizes study points proportionally to their effective sample size
(area-weighted bubble plot).

nowgt displays all study points at a uniform size.

regline overlays the fitted weighted regression line.

sumline draws a vertical reference line at the summary log DOR from the
estimation model.

pointopts(scatter_options) overrides the default study point
style (default: open circles, grey fill), e.g.
pointopts(mcolor(navy) msymbol(circle_hollow)).

regopts(line_options) overrides the default regression line
style (default: dashed thin), e.g.
regopts(lcolor(maroon) lwidth(medium) lpattern(solid)).

level(#) sets the confidence level for the asymmetry
regression. Default is level(95). Note: many authors use level(90)
for publication bias testing.

Examples

Standard Deeks funnel with regression line:

. midas mle tp fp fn tn, id(author)

. midas pubbias, wgt regline

Custom styling with summary reference line:

. midas pubbias, wgt regline sumline pointopts(mcolor(navy)) regopts(lcolor(maroon) lwidth(medium))

Unweighted, 90% level:

. midas pubbias, nowgt regline level(90)

References

Deeks JJ, Macaskill P, Irwig L. The performance of tests of publication bias
and other sample size effects in systematic reviews of diagnostic test accuracy
was assessed. Journal of Clinical Epidemiology 2005;58:882–893.
https://doi.org/10.1016/j.jclinepi.2005.01.016

Egger M, Davey Smith G, Schneider M, Minder C. Bias in meta-analysis detected
by a simple, graphical test. BMJ 1997;315:629–634.
https://doi.org/10.1136/bmj.315.7109.629

Also see

midas, midas binsse