Purpose: We describe a modified Delphi method used to select effective state vocational rehabilitation agency practices to prioritize rehabilitation services for individuals with most significant disabilities within the context of Order of Selection, an area where there is little known and published. Specifically, we describe how we applied the Delphi method to case study selection, the methods challenges we faced, and how we addressed those issues. Implications for future research are also discussed. Method: We used a structured nomination process to identify potential practices. An expert panel (N = 12) provided input on the development of indicators of effective rehabilitation practices and rated the nominated practices. Results: Selection of the practices for case study research was based on the ratings from the expert panel, including quantitative and qualitative feedback. Of the 10 practices considered by the panel, the 7 practices with the highest ratings were included in the sample. Conclusions: Using the collective expertise of panelists through a modified Delphi process to select the final case study sample was effective for this research. The panel provided an objective, group-level perspective on the merit of the practices as well as the fit with the goals of the case study.