We discuss two common ways that assessment tests or probes have been given in relation to training during applied behavioural interventions when continuous assessment is not possible. With pre-session assessment, target behaviours are tested immediately before training sessions; with post-session assessment, target behaviours are tested immediately after training sessions. Although they are not optimal methods for testing performance, such assessments are not rare, and archival data on the incidence of these two methods for JABA publications in the period 1993 to 1996 show that about 25% of research articles use one or both of these methods. The distinction between pre- and post-session assessment is important because the two methods influence the interpretation of data, and the decision to move to the next phase of an intervention. This influence is illustrated with a comparison between two studies of correspondence training. We then discuss the different positive and negative aspects of each assessment type, and two new methodologies are developed that retain the positive aspects of each assessment type. The final recommendation when such designs are necessary is a new method in which a criterion of three correct post-session assessments is reached first, followed by three correct pre-session assessments, before moving into the next phase of intervention.