Negative search

Check whether anyone actively looked for counterexamples, nulls, and failures, or only collected the hits.

Every parent you've asked about the daycare you're considering loves it. But notice who you asked: families currently enrolled, the ones who stayed. The unhappy families left, and departure took their stories out of your sample before you ever arrived.

The move is to check whether anyone actively looked for the counterexamples, the nulls, and the failures, or whether the record only ever collected hits. The cue is uniformly glowing evidence with no visible attempt to find the other side. Steps: seek the missing cases directly (find two families who left and ask why), ask the institution what complaints recur, probe the reverse direction (any kids who did worse there?), and consider artifacts in your sampling (happy parents are the easiest ones to reach, and the director introduced you to them). When it works, one of two things happens: the glowing picture survives a genuine attempt to break it and earns your trust, or a pattern surfaces, like every family leaving around age two, that no number of positive interviews would have shown. Don't run the hunt when negatives are already being systematically collected and reported; then reading the existing record honestly is enough.