The SSDI crossover view scores each shooting discipline you select on its own terms, then compares shared domains across them. The 3 cross-cutting items (self-diagnosis ability, practice structure, competition transfer) are asked once and applied to every discipline you selected.
A gap that shows up in only one discipline points to something technique-specific. A gap that shows up across all of them points to something general. The crossover view makes that distinction visible.
Most shooters who shoot two or three disciplines pick the second one up without ever testing which habits transferred cleanly and which carried a bad pattern across. A separate single-discipline quiz cannot catch that — it only sees its own answers. The crossover view asks the same shared items once and scores them against every discipline selected, so a practice-structure gap that shows up everywhere, or a fundamentals strength in rifle that hides a fundamentals weakness in pistol, surfaces in one pass rather than being missed entirely.