A thought mentioned by WhatAmIDoing brought up in a meeting:
Data how long it takes on a proposed patch until a first review happens. Likely as percentile ranks / box plots.
Internal non-public task: https://gitlab.com/Bitergia/c/Wikimedia/support/issues/62
== Implementation as of December 2019: ==
The `Repositories` gadget shown on both https://wikimedia.biterg.io/app/kibana#/dashboard/Gerrit and https://wikimedia.biterg.io/app/kibana#/dashboard/Gerrit-Timing has `Avg. Time First Review (Days)` and `Median Time First Review (Days)` columns so one can see per repository how long it takes until the first review. Note that this data is really the time it takes until a frist review happen. It is not the time how long patches are open which have not received any review.
In the DB, Time to first review data is available in the enriched index (`time_to_first_review` for changeset and `patchset_time_to_first_review` for patchsets) if we wanted to visualized things in different ways.