Native Insights vs third-party analytics: where they diverge

Native Insights vs third-party analytics: where they diverge
n=70 accounts, reconciled over a 30-day window.
— Reach numbers: agreement within 2% (third-party pulls the same API)
— Best-time-to-post recommendations: agreed only 41% of the time
Third-party 'optimal time' tools lean on aggregate cross-account medians; native uses your followers' actual activity. On accounts under 5k, your own sample is too thin and the aggregate often wins.
So what: trust native for raw metrics. Treat third-party 'best time' as a starting hypothesis, not an answer — and only above ~5k followers where your own data has signal.