Data management→Statistics
A missing start date looks like a routine query. It damages the primary endpoint.
The rescue medication page needs a start date because, eighteen months earlier, a statistician chose a strategy for that intercurrent event. A gap there doesn't just raise a query — it changes which values count in the primary analysis. The data manager cleaning the form has no way to know that.
What it costs: the primary result rests on a field nobody prioritised.
Data management→Statistics
A visit that happened ends up in no analysis at all.
Subject 0104-1003 has two HbA1c results in the baseline window — one at screening, one on Day 1. The SAP says the one closest to the target day counts; the other stays in the dataset, flagged out of every analysis. The site did everything right. There was never a query. One result still vanishes from the number — by a rule written before the study began.
What it costs: an argument at lock that neither side can win, because they're reading different documents.
Statistics→Data management
A plausible weight passes every check. The interim can never be rerun.
A transposed body weight — 46.8 instead of 84.2 — is a possible human weight, so no edit check fires. A person finds it three weeks later, in a listing sorted by change from baseline — after the interim data cut. The statistician who designed the checks never saw the listing; the data manager never knew the interim was already frozen.
What it costs: an interim and a final that disagree, and a paragraph in the CSR explaining why.
Programming→Medical writing
The writer describes a number they can't follow back.
"LS mean change −1.14" goes into a sentence. What model produced it, which subjects it includes, why one subject's Week 26 value isn't in it — the writer has the table, not the trail. The programmer has the trail, and nobody asked. Review comments go back and forth for a week.
What it costs: a CSR cycle spent reconstructing what one trace shows in a minute.