Pre- and post-session assessments: Problems and recommendations

We discuss two common ways that assessment tests or probes have been given in relation to training during applied behavioural interventions when conti nuous assessment is not possible. With pre-session assessment, target behav iours are tested immediately before training sessions; with post-session as sessment, target behaviours are tested immediately after training sessions. Although they are not optimal methods for testing performance, such assess ments 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 re search articles use one or both of these methods. The distinction between p re- and post-session assessment is important because the two methods influe nce 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 posi tive and negative aspects of each assessment type, and two new methodologie s are developed that retain the positive aspects of each assessment type. T he final recommendation when such designs are necessary is a new method in which a criterion of three correct post-session assessments is reached firs t, followed by three correct pre-session assessments, before moving into th e next phase of intervention.