1999) was conducted on a convenience sample of 10 mother-infant pairs: five SAMs who participated in IMPEP classes and five non-SAMs who participated in PEP classes only.
Again, although statistical significance was not achieved with this limited sample, IMPEP SAMs demonstrated lower PS scores at post-test compared to controls and there was a notable trend toward reduced PS scores within the IMPEP group following the intervention.
Pilot Study III (Porter, Cameron, Haran, Orukotan, & Williams-Welch 2000) was conducted on a convenience sample of 16 parent-infant pairs, with 6 in the experimental IMPEP group and 10 enrolled in PEP classes only.
Changes in pre- and post-test attachment scores were non-significant for both groups, and although the IMPEP group had lower attachment scores compared to PEP subjects at post-test, these differences existed at baseline and were likely a consequence of the non-randomized study design.
The IMPEP distinguishes itself as an innovative intervention in several ways.