Dear collegues,
Does anyone know, how I can generate a p-value for an Odds Ratio using R or Mplus concerning a multilevel (multiple/simple) logistic regression model?
Thank you very much in advance!
Best regards
Robin
Robin Junker
I just realized I didn't answer your question on p-value. You'll have to calculate it manually. Here's the reference: https://www.bmj.com/content/343/bmj.d2304
The calculation is trickier for ratio measures, such as risk ratio, odds ratio, and hazard ratio. We need to log transform the estimate and confidence limits, so that Est, l, and u in the box are the logarithms of the published values.
For example, in a meta-analysis of several studies comparing single versus bilateral mammary artery coronary bypass grafts Taggart et al presented a hazard ratio of 0.81; 95% CI 0.70 to 0.94.5 They did not quote the P value.
Following the steps in the box we calculate P as follows:
- Est = log(0.81) = −0.211
- l = log(0.70) = −0.357, u = log (0.94) = −0.062
- SE = [−0.062 − (−0.357)]/(2×1.96) = 0.0753.
- z = −0.211/0.0753 = −2.802. We take the positive value of z, 2.802.
- P = exp(−0.717×2.802 − 0.416×2.8022) = 0.005.
Please check this discussion:
https://stats.stackexchange.com/questions/8661/logistic-regression-in-r-odds-ratio
There is an answer there concerning epiDisplay package in R. The logistic. display function on glm object produces both OR, CI and p-values for predictors in glm.
Thank you @Dario Pavic for you quick answer. Unfortunately, I fear this solution only works with glm (not with glmer). Since I need to use glmer for multilevel logistic regression I can not use this code.
Robin Junker
Ok, I used "by hand" method from the same thread. I used the example from the documentation page for glmer function ( https://www.rdocumentation.org/packages/lme4/versions/1.1-21/topics/glmer )
Code:
library(lme4)
library(lattice)
xyplot(incidence/size ~ period|herd, cbpp, type=c('g','p','l'),
layout=c(3,5), index.cond = function(x,y)max(y))
(gm1
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