Presession pairing is a well-documented behaviour analytic practice that supports the development of a positive instructional environment and is associated with reduced rates of challenging behaviour among children with developmental disabilities. However, there is limited research evaluating the impact of presession pairing on children's skill acquisition rates. Therefore, in the current study, four behavioural therapists were systematically trained in an established presession pairing protocol and using a multiple baseline across participants design, the impact of this training on life skill acquisition rates among a group of four children with Autism Spectrum Disorder was evaluated. A robust improvement rate difference was calculated for each child and a robust omnibus improvement rate difference showed that the impact of training therapists in the presession pairing protocol had a very small effect on the children's life skill acquisition rates. These findings were discussed in the context of the importance of reporting null findings and designing replication studies that provide an understanding of why an effect was not demonstrated, in order to develop and refine clinical practice.