Although over 15 years have passed since Witt (1990) noted that no empirical evidence exists to support the contention that a collaborative approach to consultation leads to more positive outcomes than a hierarchical or expert driven approach, this issue generally remains unaddressed (Schulte & Osborne, 2003). While the literature documenting the benefits of consultation has continued to grow, a true head-to-head comparison has not been conducted. The purpose of the present study was to directly address Witt's call by empirically examining the impact of two consultation styles on a critical variable, practitioner treatment integrity. It was hypothesized that the involvement of practitioners in all aspects of intervention design would increase their level of treatment integrity. Two single-subject experiments using multiple baseline across subjects designs were used to examine the difference in level of treatment integrity for an imported, expert-driven intervention and a partnership-designed intervention. The first experiment was divided into three phases: (a) Phase I, Expert-driven Model; (b) Phase II, Treatment Integrity Intervention; and (c) Phase III, Partnership Model. The second experiment presented the three phases in reverse order to address the possibility of presentation effects: (a) Phase I, Partnership Model; (b) Phase II, Expert-driven Model; and (c) Phase III, Treatment Integrity Intervention. In general, the five participants who completed the three phases of the experiments demonstrated higher levels of treatment integrity during the partnership phase. Overall, the results suggest that engaging with consultees in a collaborative approach may increase the level of integrity with which the intervention is applied. (Contains 2 tables and 2 figures.)