You are an engineering manager for a B2B creative collaboration platform. Six months ago, your team invested 14 engineer-months in reliability work across the document save pipeline, build times, and incident response tooling instead of shipping user-facing features. Since then, Sev-1 incidents fell from 6 per quarter to 2, median build time dropped from 28 minutes to 16, and crash-free sessions improved from 99.1% to 99.7%, but revenue growth and weekly active teams were roughly flat. Leadership wants to know whether the investment is paying off before approving another similar program next half.
How would you evaluate whether this engineering investment created meaningful business value, and how would you separate true impact from normal quarter-to-quarter variation or unrelated product changes?