Retrospective consecutive controlled case series of outcomes for functional analyses of severe destructive behavior

Weber’s team pulled 135 clinic charts of kids and adults who had a full functional analysis for severe hitting, biting, or head-banging.

They counted how often the first FA showed a clear reason for the behavior and how often staff had to change the test.

The very first analysis gave a clear answer for a large share of clients.

When results were muddy, clinicians added extra conditions like alone time or attention extinction; after tweaks another a large share showed a pattern.

Only a large share stayed undifferentiated even after changes.

Feinstein et al. (1988) first proved that treatments matched to FA results work better; Weber now shows most clinic cases can reach that match in one or two tries.

Lambert et al. (2022) used those FA answers in a university practicum and still saw some clients fail; the new data explain why—about one in ten FAs never clear up, so treatment has to stay flexible.

Kaur et al. (2025) surveyed 76 case-series papers and flagged the same Hagopian model Weber followed, confirming this design is now a standard clinical snapshot.

You can tell funders and parents that a clear ‘why’ for severe behavior shows up seven times out of ten on the first test. When it doesn’t, build a backup condition right away instead of repeating the same one. Track your own hit rate; if you are under a large share, check your standard conditions.