Marketers love a precise-looking number — 9.06 sounds more credible than 9 — but more decimal places say nothing about whether a measurement is valid. Precise isn’t the same as useful.
Three questions worth asking about any health statistic: Does it actually measure what it claims to (construct validity)? Does it capture the whole concept, or just a slice of it (content validity)? And does it generalize to people who look like you (external validity)? A number’s precision says nothing about any of these. When it comes to using numbers to tell the truth, validity is what matters — not decimal points.
End of field note 10