On Sleuth dashboards the change lead time and breakdowns are the averages for each deploy across the period.
On the deploy view the change lead time and breakdowns are the averages for each pull request that was deployed.
You can view the individual change lead time and breakdowns for an individual pull request view the PRs tab on the deploy view.
Change failure rate
Change failure rate is defined for each project and environment. The failure conditions are determined by the Impact integrations you've setup. We recommend that you read our docs on how to define failure first.
The way failure rate is calculated is Sleuth takes the number of deploys that were within your change failure sensitivity divided by the total number of deploys in the period.
For example, if you've setup the PagerDuty integration as an impact source and your team has one incident during the report period that spanned two deploys and you made a total of 20 deploys in that period you change failure rate will be: 2 / 20 = 10%.
MTTR (mean time to recovery)
Sleuth calculates MTTR for a specific project and environment pairing based on the Impact that has been configured for the Project. We recommend that you read our docs on how to define failure first.
When Sleuth detects that an Impact source is failing, e.g. an incident in PagerDuty or an elevated metric in Datadog, we create a failure period that tracks its details and the start and end period. When calculating the MTTR for a date range we take all the failure periods that happened in that range and produce the average.
For example, if you have three incidents that happened in the date period you're inspecting, one lasting 1 hour, one lasting 2 hours and one lasting 3 hours. Your MTTR will be: (1 + 2 + 3) / 3 = 2 hours.