Is there a way of investigating publications bias in a meta-analysis of single case studies? Usually one can assess publication bias using funnel plots or Egger's test to assess funnel plot asymmetry. However those methods require some estimate of the individual studies' variance. In case of single case studies such measure of variance is usually not available. So is there any way to assess publication bias in this case?
Here i provide a dummy example in R. In a meta-analysis of single case studies, all studies investigating a change in symptom score following a treatment have been assessed:
# change_score <- c(-3,-2,-1,-7,-8,-11,-1,-10,-4,-11)