The Orientation Gap being meaningful at 7 points is from Dr. Mitch Hammer and QAs' qualitative work with the IDI. There is not a published study that references this information. The consensus is that a difference of at least 1/2 of an orientation (also, one half of a standard deviation) is likely to be meaningful to a respondent in terms of the Orientation Gap (OG). If there is an OG of less than 7 points, an IDI report will indicate that a respondent has accurately estimated their orientation. It should be noted that while the range of Minimization is 30 points, this still applies. We do discuss early and late Minimization as 2 distinct experiences.
Note: Because the IDC is a bell curve, each orientation is one standard deviation from 100, with the first half of Minimization being 1 SD, and the 2nd half of Minimization also being 1 SD.