---
title: "ProxyMembership"
description: "a subject's membership in a proxy over a period, as a fact with its evidence: the verdict, the scale of association, and the likelihood where a band is calibrated"
section: concepts
address: /concepts/proxymembership
contract: 0476e35e6e275db5
---

# ProxyMembership

a subject's membership in a proxy over a period, as a fact with its evidence: the verdict, the scale of association, and the likelihood where a band is calibrated

[figure: ProxyMembership is a fact at follows scope. The drawing shows its fields and the objects that they point at.]

| property | value |
|---|---|
| kind | fact |
| scope | follows |
| key | the proxy, its version and the subject |
| store | lake:ready |
| family | record |



## Fields


| field | type | required | note |
|---|---|---|---|
| `proxy` | `id` | yes |  |
| `proxy_version` | `hash` | yes |  |
| `subject` | `id` | yes |  |
| `found_by` | `one of lexical \| behavioural \| semantic \| position \| utterance` | yes |  |
| `overlap` | `share` | no | the scale of association: the share of the subject's activity in the proxy's observable set, weighted by affinity where the proxy widens |
| `aggregate_only` | `bool` | yes |  |
| `verdict` | `one of holds \| does not hold \| not evaluable` | yes |  |
| `period` | [Window](/concepts/window) | no | a membership is a period, not a date |
| `likelihood` | [Interval](/concepts/interval) | no | from the calibration by band of association; never measured where the band has none |
| `evidence` | [EvidenceRef](/concepts/evidenceref) | yes | a membership with no evidence cannot be written |
| `strength` | [ProxyStrength](/concepts/proxystrength) | no | the proxy's strength at the time |
| `adult` | `bool` | yes | true when a room the subject used in the period is marked adult; left out of every read by default |
| `adult_share` | `share` | no | the share of the subject's rows in the period that were in rooms marked adult; absent when none was |



## Routes that use it
No route takes or returns ProxyMembership directly. The record holds it, and the objects that point at it reach it.