This report is about the problem of making transition or enrollment rate gains comparable. It is shown that measures based on the proportions themselves, i.e. the difference between proportions, the proportion ratio and the residual gain ratio do not make the gains comparable. Instead a non-linear transformation has to be done. Two such transformations are discussed: probits and logits. As shown in the report they both make the transition gains comparable. However, it is important not to base the conclusions on the transformed values directly, since they are very difficult to interpret. Instead the transformed values should be used to predict transition rates on the assumption of comparable gains. After that the observed gains are compared with the predicted ones. A problem, more important than the choice of transformation, is that of sampling error. Comparing transition rate gains means a comparison between differences and in this case the sampling error is greater than when studying mere differences. Therefore, a statistical test is appropriate when studying transition rate gains, since it provides a measure of the effect of the independent variable at the same time as it provides a statistical test of whether this effect has been changed or not. (Author/LMO)