Navigation Latency

Time from tap to destination screen interactive (TTI).

Phases

TAP → TRANSITION → VIEW_INIT → DATA_LOAD → INTERACTIVE
     |_____________________________________________|
                   Navigation Latency

When to Use

• Tab bar taps
• List item → detail screen
• Deep link → target screen
• Any screen-to-screen transition

Key Thresholds

| Rating | Duration | |--------|----------| | Good | <400ms | | Acceptable | <1s | | Poor | >1s |

Measurement Points

1. onNavigationStart - user taps (source screen)
2. onViewAppear - destination view visible
3. onContentReady - data loaded, interactive

Implementation

See references/ui-performance.md (Navigation Latency section) for:

• iOS: NavigationLatencyTracker with os_signpost
• Android: Fragment/Activity lifecycle hooks
• React Native: React Navigation listeners

Common Mistakes

• Measuring only view appear (missing data load)
• Not correlating source → destination
• Ignoring warm vs cold screen loads

Related Skills

• See skills/interaction-latency for button/tap response times (vs full screen loads)
• Combine with skills/user-journey-tracking to correlate navigation with user intent