Before we can collect instrumentation data, we need to define a schema that the data will follow and get it merged into [schemas/events/secondary repository](https://gerrit.wikimedia.org/g/schemas/event/secondary/+/refs/heads/master).
The schema should include an `event_type` field as well as fields for the other dimensions [listed in the metrics and instrumentation plan](https://docs.google.com/document/d/1gjJaW4Xx1HZlBza-wYeJWDNQv4ZAtNaIEVedr4eJkmk/edit#bookmark=id.8z82a6bi219z). A good example to follow is the [the wikistories_contribution_event schema](https://gerrit.wikimedia.org/r/plugins/gitiles/schemas/event/secondary/+/refs/heads/master/jsonschema/analytics/mediawiki/wikistories_contribution_event/current.yaml)
For full instructions on creating a schema, see [wikitech:Event Platform/Instrumentation How To#Creating a new schema](https://wikitech.wikimedia.org/wiki/Event_Platform/Instrumentation_How_To#Creating_a_new_schema).