There are some substantial ways in which the current approach to establishing an evidence base for a treatment effect works against CAM research. The standard statistical method in comparative trials is the null hypothesis test, which requires a decision that the ‘no treatment effect’ hypothesis is confirmed or rejected. While this approach is appropriate for evidence-based medicine, the requirement for a decisive result drives sample sizes upwards, or leaves small trials subject to being criticised for being underpowered. Employing the fundamental theory of hypothesis tests, it is possible to define a ‘separation test’ that avoids this problem by invoking a different inferential rationale. The purpose of a separation test is to find an indication that further research is justified or that it is not. This change in strategy can considerably lower the required sample size. Since many CAM comparative trials are in the early phases of research, where both budgetary and safety considerations argue for a small sample size, separation tests may be especially of interest to CAM researchers. There is, therefore, an opportunity for evidence-based medicine to generate a new kind of study in which the purpose is to assess whether or not it is worthwhile to pursue research on an alternative treatment, rather than to determine whether or not it has been proved effective.