Term Definition
Hadamard matrix

Hadamard matrix for 4 half samples image

Hard consistency check
A signal warning that there is an inconsistency between the current response and a previous response; the interviewer or respondent cannot continue until the inconsistency is resolved.
Hours Per Interview (HPI)
A measure of study efficiency, calculated as the total number of interviewer hours spent during production (including travel, reluctance handling, listing, completing an interview, and other administrative tasks) divided by the total number of interviews.
Synonyms - hours per interview