Capacity-Fit Matrix¶
Screening matrix — instantiates Persistent Site Framing
Matches a proposed occupant against a site's capacity and constraints before anyone is placed, so mismatches are caught on paper rather than in place.
A Capacity-Fit Matrix answers one question and only one: can this occupant go in this site? It pairs a profile of what each site can host — capacity, dimensions, environment, equipment, access, permitted behavior — against the requirements of a candidate occupant, and returns fit, misfit, or fit-with-conditions. Its defining move is that the judgment is occupant-agnostic about identity but specific about traits: the matrix does not care who or what the occupant is, only whether its measurable requirements clear the site's affordances. It is a compatibility check run before placement, so a mismatch surfaces as a red cell in a table rather than as a crisis once someone or something is already in the wrong place.
Example¶
A zoo is reshuffling animals ahead of a new exhibit and needs to know which species can go in which enclosure without discovering a problem the hard way. Staff build a Capacity-Fit Matrix: enclosures down the rows, each with an affordance profile (floor area, climb height, water feature, thermal range, barrier type, adjacency to predators), candidate species across the columns, each with requirements (space per animal, temperature band, whether it can share a wall with a natural predator). Every cell is a compatibility test. A cell lights red where a tortoise's basking-temperature need exceeds an enclosure's heating, or where a prey species would border a big-cat run; it lights amber where a modification would make it work.
The reshuffle is decided from the table. No animal is moved to find out; the matrix has already ruled out the placements that would have caused stress, escape risk, or a welfare violation, and flagged the two enclosures that need a heat lamp before they can host anything tropical.
How it works¶
The matrix has two halves that meet in each cell. The affordance profile side encodes, per site, the hosting envelope: capacities (how many, how large), environmental ranges, required equipment, access constraints, and prohibited adjacencies. The compatibility criterion side encodes, per candidate, the requirements that must be satisfied, and — critically — the rule for comparing them: a hard threshold (temperature must fall inside the band), a capacity count (occupants ≤ limit), a categorical exclusion (no predator adjacency), or a conditional (fits if a modification is made). Evaluating the pair yields fit / conditional-fit / misfit for every cell. The matrix produces a ruling, not a move: it never assigns the occupant, never records that it was assigned, and never sequences the change — it only certifies whether the pairing is allowable.
Tuning parameters¶
- Constraint strictness — how many requirements are hard exclusions versus soft preferences. Strict matrices prevent unsafe placements but reject workable ones; loose matrices are flexible but let marginal fits through.
- Profile granularity — how finely each site's affordances are described. Fine profiles catch subtle mismatches but are laborious to maintain; coarse profiles are cheap but miss edge cases.
- Conditional handling — whether "fits if modified" is a first-class result or collapsed into misfit. First-class conditionals surface cheap fixes but complicate the ruling.
- Scoring vs. gating — a pass/fail gate versus a ranked fit score. Scores help choose among several viable sites; gates are simpler and better for pure eligibility.
When it helps, and when it misleads¶
The matrix's strength is that it makes an affordance[n1] explicit and checkable before commitment — the archetype's remedy for constraints "discovered only after an unsuitable occupant is placed." It turns tacit "that won't fit" judgments into a shared, auditable table anyone can inspect.
Its failure mode is false confidence in the profile: the matrix is only as true as the affordance data, and the constraints that matter most (a subtle noise sensitivity, an unmodeled interaction between two occupants) are often the ones no column captured, so a tidy grid of green cells can certify a placement that reality rejects. A classic misuse is treating a fit ruling as an assignment — acting as though a green cell means the occupant is now placed — when it means only that placement is permitted. The guarding discipline is to keep the profile honest and current, treat green as "allowed, not done," and re-screen when either the site's affordances or the occupant's needs change.
How it implements the components¶
The matrix fills the archetype's compatibility-screening components:
capacity_and_affordance_profile— it encodes, per site, the hosting envelope (capacity, environment, equipment, adjacency) a candidate must clear.occupant_compatibility_criterion— it defines and evaluates the rule that decides whether a candidate's requirements satisfy that envelope.
It rules on eligibility only. It does not move the occupant in or out or sequence the states of that change — turnover_and_vacancy_rule and access_and_permission_policy are the Assignment and Release Workflow's, its nearest twin (the matrix says a placement is allowed; the workflow is what actually performs it under authority).
Related¶
- Instantiates: Persistent Site Framing — the matrix is the archetype's pre-placement compatibility gate.
- Consumes: Site Registry — supplies the sites whose affordances the profiles describe.
- Sibling mechanisms: Site Registry · Physical or Virtual Labeling System · Site Map or Plan · Assignment and Release Workflow · Occupancy Ledger · Site Lineage Tombstone · Vacancy Status Dashboard · Site Audit Walkthrough
Editorial Notes¶
Form Classification¶
Form family: Assessment, Review & Assurance
Rationale: Matches a proposed occupant against a site's capacity and constraints before anyone is placed, so mismatches are caught on paper rather than in place, making its operative form a bounded evaluation of existing evidence or work that produces a finding or disposition.
Independent corroboration: The frozen evidence defines Capacity-Fit Matrix as 'Matches a proposed occupant against a site's capacity and constraints before anyone is placed, so mismatches are caught on paper rather than in place', so its operative form is Assessment, Review & Assurance.
Review outcome: Independent reviewer agreement; high confidence.
Origin Attribution¶
Primary origin: Architecture & Urban Planning
Origin pattern: Convergent development
Present-day reach: Multi-domain
Rationale: Site programming and planning compare occupant requirements with spatial, environmental, access, equipment, and permitted-use constraints before placement.
Related originating lineages:
- Engineering & Design — Requirements matrices supply measurable fit, conditional fit, and vetoing incompatibilities.
- Psychology — Ecological psychology's affordance concept explains fit as what a particular environment permits a particular actor to do.
Review resolution: Architecture and planning is the agreed primary lineage because facility programming matches occupant requirements to site affordances before placement. Systems engineering independently contributes requirements matrices and psychology contributes person-environment fit; their convergence gives multi-domain reach without making this an Encyclopedia-created synthesis.
Attribution caveat: Facility programming is the clearest source, while systems requirements and person-environment fit independently use the same compatibility structure.
Review outcome: Reconciled after independent review; high confidence.
Sources consulted:
Notes¶
[n1] An affordance — from James Gibson's ecological psychology, later carried into design by Don Norman — is what an environment offers or permits a given actor. A capacity-fit matrix is affordance reasoning made tabular: each site's profile is its affordances, and the compatibility criterion asks whether a candidate can take them up. ↩