I am trying to do a metanalysis (using Wilson meta-analysis http://mason.gmu.edu/~dwilsonb/ma.html) comparing the dropout percentage of a treatment with a control group. I tried to calculate the cohen's d using binary proportions. Specifically, I calculated it from this site http://cebcp.org/practical-meta-analysis-effect-size-calculator/standardized-mean-difference-d/binary-proportions/.
The problem is that when using a treatment or control of 100% or 0% the results for probit are NaNs (not a number) or Infinite. An example would be 0/16 and 2/18. Since the values are calculated from log(0)=inf and log(inf)=NaN I considered using extreme values.
The other cohen's d values ranges from -0.2 to +1.14. I have tried to set the NaN/Inifite values fairly high such as 3, 5, 10 and 100 (and for the negatives the coresponding negative values). I have noticed that with 3 some values had non-significant results and as I increased it more values became significant. This seems to be an unreliable method. What choice of values would you suggest? Should I use the already existing extremes? Should I treat them as missing values? Any suggestions or references would be appreciated.
Please note that my background in statistics is not very strong. I am a psychologist.