Hi, I'm doing a meta-analysis in metafor. All is fine except when there are 0s in the values that i'm pooling, then i get a pooled estimate but not the I2 that i am also interested in. for example:
summary(rma.1<-rma(yi,vi,data=mix,method="ML",knha=F,weighted=F,intercept=T)) (where yi are the study outcomes, one of which is 0, and vi is the variance of the study outcomes) Random-Effects Model (k = 17; tau^2 estimator: ML) logLik deviance AIC BIC AICc 13.0539 Inf -22.1077 -20.4413 -21.2506 tau^2 (estimated amount of total heterogeneity): 0.0119 (SE = 0.0043) tau (square root of estimated tau^2 value): 0.1089 Model Results: estimate se zval pval ci.lb ci.ub 0.1837 0.0274 6.7154 <.0001 0.1301 0.2374 *** --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Warning messages: 1: In rma(yi, vi, data = mix, method = "ML", knha = F, weighted = F, : There are outcomes with non-positive sampling variances. 2: In rma(yi, vi, data = mix, method = "ML", knha = F, weighted = F, : Cannot compute Q-test, I^2, or H^2 with non-positive sampling variances. Is there any way around this? thanks Branwen ________________________________________ From: r-help-boun...@r-project.org [r-help-boun...@r-project.org] on behalf of r-help-ow...@r-project.org [r-help-ow...@r-project.org] Sent: 27 August 2014 13:36 To: Owen, Branwen Subject: Metafor -can't calculate heterogeneity with non-positive sampling variances Message rejected by filter rule match ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
