01 / Source
A public administrative record, mirrored locally.
The primary source is the Michigan Department of Corrections Offender Tracking Information System (OTIS). The local mirror retains source URLs and observation timestamps, then computes aggregate statistics for this publication.
Administrative profiles and sentence fields.
142,592 current records plus dated snapshots.
Counts, buckets, baselines, and coverage checks.
No evidence files or private submissions in charts.
02 / Scope and coverage
What the snapshot contains.
The Jul 9 aggregate contains 142,592 people and 520,942 sentence rows. A person can have multiple sentence rows, so row-level charts should never be read as unique-person counts.
| Field | Covered | Missing / uncategorized | Coverage |
|---|---|---|---|
| Core record | 142,592 | 0 | 100.0% |
| Canonical status | 142,468 | 124 | 99.9% |
| Age band | 142,552 | 40 | 100.0% |
| Binary sex field | 142,568 | 24 | 100.0% |
| Maximum sentence | 518,675 | 2,267 | 99.6% of sentence rows |
County jail populations, youth records, sealed or removed records, and court-file detail outside OTIS are out of scope. Source updates can lag real-world events.
03 / Definitions
Terms kept close to the chart.
- People in the mirror
- Distinct current OTIS records keyed by the local identity model. This is not the current prison population.
- Marked Prisoner
- Records whose current canonicalized status is Prisoner at the latest local observation.
- Sentence row
- One parsed prison or probation sentence entry. One person can contribute many rows.
- Observed event
- A change derived between local snapshots. Counts are events, not unique people or official statewide rates.
- Population baseline
- A resident-population comparison used to describe representation. It is not an explanation of cause.
- Past ERD / PBJD
- Marked Prisoner with an earliest release or parole-jurisdiction date on or before the as-of date. Eligibility is not guaranteed release.
04 / Privacy and participation
Public data and private contributions stay separate.
No user-submitted evidence or profile email enters the public data studio.
Uploaded files remain in protected object storage and are not publicly addressable.
Permission to publish anonymously is optional and never bypasses review.
Profiles, submissions, and saved views are tied to the authenticated user on the server.
05 / Aggregate downloads
Take the reviewed rows with you.
These CSV files contain only the compact aggregate rows used in the visualizations.
A gap is a research question, not a license to guess.
Use the data studio to locate patterns, then use primary records and domain expertise before making a public claim.
Return to the data studio