In part because of the complexity of the phenomena being studied as well as the tradition of qualitative research in the area, the interview approach remains a major option for assessing the Perry scheme, and arguably the richest source of data on intellectual development. We recommend that interviews be used with a sub-sample on projects using other Perry instruments, both for the richness of the quotes available from such interviews and for ongoing validation efforts of less in-depth assessment methods.

Perry and his colleagues used a very open-ended interview approach in the initial study, but over the years since then a variety of question formats have been tried, both unstructured and structured. CSID has developed a standardized “Perry Interview” protocol combining a set of standard questions with a variety of follow-up probes based, but one big advantage of interviews is that they can be modified and supplemented to fit the need of particular projects. For example, questions can be added focusing on specific areas in addition to intellectual development—e.g., faith, diversity, disciplinary perspectives, etc.

The difficulty with the interview approach is that it is expensive and time-consuming. Interviews must be scored by trained raters, and the current cost of such rating ranges from $25-$30 per interview protocol, depending on the length. In most cases ratings are done from transcripts (transcription being the other major cost issue with such a project), but we have also rated successfully from videotaped interviews.