Game days vs chaos engineering vs incident simulations
These terms get used interchangeably, and that’s a problem. They have different goals.
If you want better incident outcomes, you need to choose the right tool.
Game days
Purpose: teamwork and process rehearsal.
A game day is typically a planned exercise where teams practice:
- incident roles
- comms cadence
- escalation patterns
- coordination
Failure mode: it becomes performative. The “incident” is too scripted, and the learning doesn’t transfer to real on-call.
Use it when: you are building incident process maturity across multiple teams.
Chaos engineering
Purpose: validate system resilience under failure.
Chaos engineering deliberately injects failures to confirm:
- the system degrades gracefully
- alerts fire correctly
- redundancies work
- SLO assumptions are real
Failure mode: it becomes risky without learning structure, or it’s limited to a few specialists.
Use it when: you have meaningful coverage and the discipline to run controlled experiments.
Incident simulations
Purpose: build human operational skill through repeatable reps.
A simulation focuses on:
- diagnosis under ambiguity
- safe mitigations
- decision quality
- runbook effectiveness
- measurable improvement over time
Failure mode: it becomes too unrealistic (not aligned to real failure modes) or too infrequent to build skill.
Use it when: you want to improve readiness across engineers and reduce “hero dependence.”
What you should do first
If you are early, start with incident simulations:
- they improve skills quickly
- they reveal runbook and telemetry gaps
- they reduce on-call anxiety for newer engineers
- they generate concrete platform work (dashboards, alerts, guardrails)
Then layer in game days and chaos engineering once you have baseline maturity.
The metric that matters
Don’t measure “number of exercises.” Measure:
- time-to-diagnose trend
- time-to-mitigate trend
- runbook coverage and quality
- outcome consistency across engineers
That’s what makes the program real.
If you want a practical simulation to run next week, pick a common failure mode (retry storm, dependency degradation, consumer lag) and run it end-to-end with a timebox and a structured debrief.