Measuring Success

We tracked four key metrics throughout the migration. System coverage measured the percentage of UI rendered by design system components (target: 90% within 6 months — we hit 87%). Component adoption rate tracked how many teams were using each new component within two weeks of release (target: 3 of 4 teams — we averaged 3.2). Design-to-dev handoff time measured how long it took engineers to implement a designer's spec (dropped from an average of 4.2 days to 1.8 days). CSS bundle size tracked the total stylesheet payload (reduced by 34% as we removed Bootstrap overrides). The metric I wish I'd tracked from the start: designer satisfaction. We only started surveying the design team in month 3, but the qualitative feedback about feeling more confident and spending less time on pixel-pushing was arguably the most important outcome.