institution/Wiki/gangs/Joining.md

# Joining a gang

*How Gangs decides who runs with a crew — and why a well-run colony keeps almost everyone out.*

Membership is not random, and it is not a mood event. A pawn joins a gang only when their **disposition
and their circumstances line up at once** — the same `Nature × Nurture` engine that drives every other
behaviour in the Institution suite. This page covers the exact test, why the bar is set where it is,
and how you keep pawns on the right side of it.

## The rule

```
WouldJoin(pawn) == Propensity.Nature(pawn) * Propensity.Nurture(pawn) >= JoinThreshold
JoinThreshold = 0.9
```

Two gates before the maths even runs:

| Guard | Effect |
|---|---|
| `pawn == null` | never joins |
| not `RaceProps.Humanlike` | never joins — animals and mechs are out |

Then it is one line: multiply the pawn's **Nature** by their **Nurture** and compare to **0.9**. There
is no dice roll here. `WouldJoin` is a deterministic threshold on the two propensity scores, so the
same pawn in the same situation always gives the same answer — join, or don't. (This is different from
Core's `Propensity.Would(...)`, which *is* a seeded random roll used for one-off acts like a piss
spree. Gang membership is a standing condition, so it uses the raw product.)

### The two halves

Both terms come from **Institution: Core** — see Core's own documentation for the full tables — but you
need the shape of them to understand the bar:

- **Nature** (`0..1`) is *who the pawn is*: a base of `0.05`, plus trait weights, clamped to `[0, 1]`.
  Psychopath `+0.45`, Bloodlust `+0.35`, Kleptomaniac `+0.40`, Greedy `+0.25`, Abrasive `+0.15`;
  and it goes **down** for Kind `−0.30` or Ascetic `−0.15`. This is fixed at pawn creation and barely
  moves.
- **Nurture** (a multiplier, `~≥ 0.4`, base `1.0`) is *the situation you put them in*: a floored mood
  multiplies it up hard (roughly `×2.5` under 0.20 mood, `×1.6` under 0.35), being held while
  miserable adds more (`×1.4`), a hardened record (negative reform) raises it, and — critically —
  **deterrence pulls it down** (`×Lerp(1.3, 0.7, deterrence)`, neutral `1.0` at baseline order, so a
  high-deterrence colony scales nurture toward `0.7`). This is the half you control.

## Why the bar is high

`0.9` is a deliberately steep threshold. From the source, in its own words:

> A high bar, on purpose: gangs are a symptom of a badly-run colony, not furniture. A healthy Rimworld
> — content pawns, an orderly colony — grows few gangs, if any.

Because the two terms are **multiplied**, both have to be substantial for the product to clear `0.9`.
A nasty pawn in a happy, policed colony has a low nurture and stays out. A saintly pawn in a hellhole
has a near-zero nature and stays out. You only get a gang when a genuinely disposed pawn is *also*
neglected or unpoliced — foul streak **and** bad situation, together.

That is the design speaking through the arithmetic: a gang is never bad luck. It is feedback.

## Worked examples

All numbers below use Core's documented factors; the intermediate nurture figures are rounded to show
the shape of the decision.

| Pawn | Nature | Situation → Nurture | Product | Joins? |
|---|---|---|---|---|
| **Kind colonist**, ordinary life | `0.05 − 0.30 → 0.00` (clamped) | content, `≈ 1.0` | `0.00` | **No** — nature floors it |
| **Greedy prisoner**, content, policed | `0.30` | fed & high deterrence, `≈ 0.7` | `≈ 0.21` | **No** |
| **Greedy prisoner**, starved & neglected | `0.30` | mood floored + held, `≈ 3.5` | `≈ 1.05` | **Yes** |
| ...same pawn, but you raise deterrence | `0.30` | `× ≈ 0.7` → `≈ 2.45` | `≈ 0.74` | **No** — deterrence tipped them out |
| **Psychopath + Bloodlust**, mood floored | `≈ 0.85` | mood floored + held, `≈ 3.5` | `≈ 2.9` | **Yes** — nothing short of reform pulls this back |

The middle rows are the whole game of it. The **same greedy prisoner** joins or abstains purely on how
you run the wing. The Kind colonist and the near-maxed psychopath are the fixed poles: one essentially
cannot join, the other essentially always will if you neglect them. Everyone in between is a policy
choice.

The mod's own integration test asserts exactly these poles: a psychopath-plus-bloodlust pawn with a
floored mood returns `WouldJoin == true`, and a Kind colonist in ordinary circumstance returns
`WouldJoin == false`.

## It works for every pawn, everywhere

There is no "prisoners only" special case. The comment is explicit:

> Any pawn — colonist, prisoner, slave — can, wherever they are.

`WouldJoin` reads nothing about a pawn's secured status. A disposed **free colonist** can run with a
crew on the outside; a **prisoner** can run with theirs on the inside; a **slave** likewise. This is
what lets a gang span the wall — an outside member and an inside member of the same crew (see
[Networks and Smuggling](Networks-and-Smuggling.md)). Being held raises nurture (misery), but it is not
a requirement.

## The cadence: the 5000-tick check

Membership is re-evaluated on a fixed interval by the gang map component:

```
CheckInterval = 5000 ticks
MapComponentTick: run only when TicksGame % 5000 == 0
```

**5000 ticks** is about **2 in-game hours** (a RimWorld day is 60,000 ticks), or roughly **80 seconds**
of real time at normal (1×) speed. On each fire, the component:

1. Gathers `crew` — every spawned humanlike on the map for whom `WouldJoin` is currently true.
2. Pairs up unaffiliated members of `crew` who **share a room and a bond** into gangs (see
   [Affiliations and Segregation](Affiliations-and-Segregation.md)).
3. Runs one round of network resupply inside each gang (see
   [Networks and Smuggling](Networks-and-Smuggling.md)).

Because the check re-reads `WouldJoin` every time, membership is *live*: a pawn whose situation improves
past the point where the product drops back under `0.9` simply stops being eligible to form new bonds.
The bar is not a one-time gate at recruitment — it is a standing condition the colony is continuously
graded against.

## How to keep pawns out

You do not fight the gang system. You lower nurture, which lowers the product, which drops pawns below
`0.9`:

- **Feed them and give them recreation.** Mood is the biggest nurture multiplier by far. A wing above
  0.35 mood loses the `×2.5`/`×1.6` spikes entirely.
- **Keep deterrence high** (Institution: Justice). Deterrence scales nurture down toward `0.7`; a
  well-policed colony is *arithmetically* less gang-prone. This is the row in the table above where the
  same greedy prisoner flips from *joins* to *abstains*.
- **Reform, don't just punish.** A hardened record (negative reform) *raises* nurture; discipline that
  actually reforms (positive reform) lowers it. Harsh punishment that prisonizes a pawn makes the
  gang problem worse, not better.
- **Accept the two poles.** A near-maxed psychopath will run with someone the moment you slip; a Kind
  pawn essentially never will. Spend your attention on the middle.

---
*Part of the **Institution** suite — Core · Contraband · Justice · Gangs (this). Each mod stands alone; together they are one system.*
**