Glossary of Housing Lottery and Waitlist Terms

The vocabulary of housing lottery administration is scattered across federal regulations, state programs, and agency practice, and nobody has collected it in one place. This page is that collection: plain-language definitions written for practitioners, not lawyers, from seven years of processing real lotteries.

Terms are alphabetical, and every heading is a stable link: cite or link to any definition freely. The acronym decoder is at the bottom. If a term you need is missing, or a definition doesn't match how the word is used in your program, tell us.

A

Admission preference

A category of applicants an agency has chosen to house sooner than others: veterans, local residents, people experiencing homelessness, and so on. Preferences must appear in the agency's written admission policy and cannot be based on protected characteristics. See also preference tier, residency preference.

Admission and Continued Occupancy Policy (ACOP)

The written policy governing a public housing program: who is eligible, how the waiting list is ordered, what preferences apply, and how units are offered. The ACOP is the document a lottery must match: a drawing run contrary to the written policy is a finding waiting to happen. The Housing Choice Voucher equivalent is the administrative plan.

Administrative plan

The written policy governing a Housing Choice Voucher program, including how applicants are selected from the waiting list. Federal rules require the plan to state the selection system the agency actually uses: a lottery is permitted, but only if the plan says so and the agency follows it.

Affordable housing lottery

The general public's term for any random drawing that decides access to below-market housing: a PHA waitlist drawing, a LIHTC lease-up, or a municipal inclusionary lottery. Practitioners usually name the specific kind; applicants and journalists say "housing lottery."

Applicant pool

Everyone who submitted a valid entry before the application window closed. The pool is what gets frozen as the preserved source file: the lottery's input, kept exactly as it existed when entries closed.

Application window

The published period during which applications are accepted for a waitlist opening. Because a lottery (unlike first-come, first-served) gives every entry in the window equal standing, the window's exact open and close times belong in the record.

Area Median Income (AMI)

The midpoint household income for a metro area or county, published annually by HUD and used to set program income limits. Bands are expressed as percentages: "extremely low income" is at or below 30% of AMI, "very low income" at or below 50%, "low income" at or below 80%. Lottery eligibility is usually defined in AMI terms.

Audit trail

The connected chain of records showing what happened, when, and in what order, for a lottery: the preserved input, the draw order, per-entry timestamps, and the contemporaneous log. An audit trail that can be edited without detection is a narrative, not a trail; see tamper-evident record.

B

Board resolution

A formal vote of an agency's governing board, recorded in minutes. Opening a closed waiting list, adopting a lottery as the selection method, and amending the ACOP or administrative plan typically require one. The resolution, and the policy version it adopted, are part of a defensible lottery record.

C

Centralized waiting list

A single waiting list shared by several agencies or properties in a region, in place of separate lists at each. Centralization simplifies applying but raises the documentation stakes of any one drawing, since a single lottery now orders applicants for many programs at once.

Chain of custody

An account of who held a record, when, and what they could have done to it, from creation to production. The question a lottery record must survive ("how do I know nobody changed this?") is a chain-of-custody question. The strongest answer is a record that proves its own integrity; see tamper-evident record.

Closed waiting list

A waiting list not currently accepting applications. Agencies close lists when projected wait times become unreasonable. Reopening a closed list is a formal process: public notice, an application window, and usually a lottery, covered step-by-step in Opening a Closed Waiting List.

Contemporaneous log

A log written while the events it describes are happening, as opposed to a summary written afterward. Contemporaneous records carry evidentiary weight that reconstructions do not: auditors distinguish sharply between the two, and courts more so.

Cryptographically secure random number generator (CSPRNG)

A random number source strong enough that its output cannot be predicted or reconstructed, even by someone who has seen previous output. Spreadsheet functions like RAND() are not cryptographically secure: they are designed for statistical simulation, not for decisions someone might contest. Why that matters is the subject of Why a Spreadsheet Isn't Evidence.

D

Denial notice

The written notice an applicant receives when found ineligible, with the reason and the right to review. Not part of the lottery itself, but lottery records get pulled into denial disputes: another reason the draw order must show every position, not just selectees.

Disparate impact

A legal theory under which a neutral-seeming policy violates fair housing law because of its unequal effect on a protected class, regardless of intent. Selection policies (including preferences layered onto a lottery) are analyzed this way. A residency preference in a segregated jurisdiction is the classic caution.

Draw order

The complete output of a lottery: every entry, in the sequence drawn, through the last position, not just the winners. Waiting lists get worked far deeper than anyone expects, and a record that stops at position 40 is useless in month fourteen when position 41 is being called.

Drawing

The event itself: the applicant pool goes in, a random process runs, and an ordered list comes out. The drawing is a moment; the record of it is what lasts. See How Housing Lotteries Actually Work for the mechanics.

Duplicate application

More than one entry from the same household in a single lottery. Every lottery policy needs a stated de-duplication rule (typically: all duplicates removed, or the most recent kept) applied before the drawing and noted in the log: removing entries after the draw order exists invites exactly the challenge good documentation prevents.

E

Eligibility screening

Verification that an applicant qualifies: income, household size, program-specific criteria. Programs differ on sequence: screen everyone before the lottery, or lottery first and screen in draw order. Both are defensible; the policy must say which one applies, and the record must show it was followed.

Entry

One application's presence in the drawing. Depending on program design, an entry may represent a household, an application, or (in a weighted lottery) one of several chances the same household holds.

F

Fair Housing Act

The federal law prohibiting housing discrimination on the basis of race, color, religion, sex, national origin, familial status, or disability. It applies to selection systems in full: a lottery does not exempt an agency from fair housing analysis, though a properly documented random drawing is strong evidence that selection ignored protected characteristics.

First-come, first-served (FCFS)

Ordering applicants by when they applied instead of by lottery. Simple, but it advantages people with flexible schedules, fast internet, and early information, which is why oversubscribed openings have widely shifted to lotteries, where the entire application window is equal.

Fisher–Yates shuffle

The standard algorithm for putting a list in random order without bias: every possible ordering equally likely, provided the randomness feeding it is sound (see CSPRNG). The algorithm is not the hard part of a defensible lottery; proving what it produced is.

H

Housing Choice Voucher (HCV)

The federal program (commonly still called Section 8) in which a household rents on the private market and a PHA pays a subsidy to the landlord. HCV waiting list openings are the largest lotteries in housing: a single metro opening can draw tens of thousands of applications in days.

Housing Finance Agency (HFA)

A state agency that finances affordable housing and, in most states, allocates Low-Income Housing Tax Credits. For LIHTC lease-up lotteries, the HFA (as allocating agency) is the body whose rules and monitoring apply.

HUD (U.S. Department of Housing and Urban Development)

The federal department that funds and regulates public housing and HCV programs, chiefly through its Office of Public and Indian Housing (PIH). HUD does not prescribe a lottery method: it requires that an agency's written policy state its selection system and that records be kept and produced on demand.

I

Inclusionary housing

Below-market units created by local ordinance requiring or incentivizing developers to include them in market-rate projects. Inclusionary lotteries are run by cities or their designees under local rules: a growing share of all housing lotteries, and the part of the field with the widest variation in documentation practice.

Income targeting

Federal requirements directing a share of new admissions to the lowest-income bands: at least 75% of new HCV admissions and 40% of new public housing admissions must be extremely low income. Targeting interacts with lottery design: an agency may need to select in a way that satisfies these ratios, and the policy should say how.

Informal review / informal hearing

The process through which an applicant contests a denial (review) or a participant contests an adverse action (hearing). This is a common venue where lottery documentation is actually examined: the question is usually "show me how this applicant ended up in this position."

L

Lease-up

The period when a new or renovated property fills its units for the first time. Oversubscribed lease-ups (particularly LIHTC and inclusionary projects) are run as lotteries, often under a tenant selection plan rather than an ACOP.

Local preference

An admission preference defined by the agency to reflect local needs, as distinct from any federal preference. Must be in the written policy, applied as written, and analyzed for fair housing effect. See also residency preference.

Lottery

In housing administration: a random process that orders or selects applicants when demand exceeds supply. A lottery's legitimacy rests on two separable claims: the process was random, and the record of it is intact. Most challenges attack the second claim, not the first.

Low-Income Housing Tax Credit (LIHTC)

The federal tax credit program that finances most new affordable rental housing in the United States, administered by state allocating agencies under each state's Qualified Allocation Plan. Oversubscribed LIHTC lease-ups commonly select by lottery, and state monitoring (not HUD) governs the records.

M

Micro-purchase threshold

The dollar level below which federal procurement rules allow purchase without competitive quotes: $10,000 for most purchases under the federal uniform guidance, with many agencies setting lower internal limits. Relevant to lottery administration because services priced under the threshold can typically be bought on a purchase order without a formal procurement.

N

NAHASDA

The Native American Housing Assistance and Self-Determination Act: the framework under which tribally designated housing entities run their programs. Tribal housing lotteries answer to NAHASDA and tribal policy rather than the public housing rules, which is why documentation requirements must be checked against the tribe's own program documents.

Neutral third party

An entity with no stake in a lottery's outcome that conducts the drawing and produces the record. Organizational separation answers the objection no internal process can fully answer ("you could have changed it") because the agency never controls the record's creation. An agency can still run a well-documented lottery internally; see the documentation checklist for what that takes.

O

Open waiting list

A waiting list currently accepting applications, either indefinitely or for a stated application window.

Oversubscription

More valid applications than available units or slots: the condition that makes a lottery necessary at all. Oversubscription ratios in urban openings routinely exceed ten to one and can reach the hundreds.

P

Per-entry timestamp

A distinct recorded time for each draw in a lottery, as opposed to a single completion time for the whole run. A sequence of timestamps demonstrates a process that unfolded over time, which is far harder to fabricate after the fact than one line in a log.

Personally identifiable information (PII)

Information that identifies a specific person: names, addresses, contact details, identification numbers. Lottery inputs are dense with PII; lottery outputs need not be. Producing a PII-free version of results at the same time as the full version is the difference between publishing on schedule and redacting under pressure.

Preference tier

A level in a selection hierarchy: all applicants in a higher tier are ordered ahead of everyone in lower tiers, with the lottery ordering applicants within each tier. Distinct from weighting, where favored applicants get better odds but no guarantee of ordering ahead of anyone. Confusing the two is among the most common (and most consequential) policy drafting errors in lottery administration.

Preliminary application (pre-application)

The short form used during a waitlist opening, collecting only what's needed to place a household on the list; full verification happens when the household nears the top. Most large lotteries draw from pre-applications, which keeps the drawing's input simple and its PII exposure lower.

Preserved source file

An exact, unmodified copy of the applicant list as it existed the moment the drawing ran, not the working file that continued to be edited afterward. The single most commonly lost component of a lottery record, because the applicant list is a living file right up until it must stop being one.

Project-based voucher (PBV)

An HCV subsidy attached to a specific unit rather than carried by the household. PBV waiting lists are typically separate, site-based lists, meaning an agency can be running several lotteries under different lists in one year.

Protected characteristics

The attributes on which selection may not lawfully turn, under the Fair Housing Act: race, color, religion, sex, national origin, familial status, and disability; admission rules add criteria such as age. A genuinely random drawing cannot consider characteristics it never received, which is a lottery's quiet compliance advantage.

Public housing

Housing owned and operated by a housing authority and rented directly to low-income households. One of the two classic PHA programs (with HCV), each with its own waiting lists and selection rules.

Public Housing Agency (PHA)

The federal statutory term for a housing authority: the local government entity administering public housing and/or HCV programs. Roughly 3,300 exist nationwide, from agencies managing a few dozen units to authorities serving whole metros.

Public notice

The published announcement of a waitlist opening: what's opening, when the window runs, how to apply, and how selection will work. Required by federal and local rules, and the first document a challenge will examine: if the notice said "lottery," the record must show one.

Public records request

A request under state open-records law (or FOIA for federal agencies) to produce agency documents. Lottery results and logs are reachable this way, which is why the PII-free version of the record should exist before anyone asks. See also redaction.

Purge (waitlist purge)

A periodic update of a waiting list, removing households that no longer respond or qualify. Purges are legitimate list maintenance, but a purge between a drawing and a challenge is exactly why the original draw order must be preserved untouched, separate from the working list.

R

Random selection

Any selection method in which chance, rather than order of application or staff judgment, determines outcomes. Not federally mandated: a permitted local method that an agency's written policy must name and follow.

Redaction

Removing PII from a record before release. Redaction done under deadline pressure is a leading cause of accidental disclosure, which is the argument for generating a public-safe version of lottery outputs at the moment they're created rather than when a request arrives.

Residency preference

A preference for applicants who live or work in the jurisdiction. Lawful when adopted properly, but the most litigated preference type: where a jurisdiction's demographics differ sharply from its region's, a residency preference can produce disparate impact. Draft with counsel; document with care.

Retention period

How long records must be kept. Federal HCV rules set a three-year minimum; LIHTC monitoring generally requires longer; state and local programs set their own terms; and anything touching an active challenge should be kept until final resolution regardless of minimums. Details and citations in the documentation checklist.

S

Section 8

The common name for the Housing Choice Voucher program, from its section of the U.S. Housing Act of 1937. Still the term applicants, landlords, and most coverage use.

Seed (randomization seed)

The starting value a random number generator expands into its output. In a lottery context the seed's handling matters: a process whose seed is disclosed in advance can be gamed, and one whose seed is chosen after entries are known can be steered. Sound designs draw seeds from a CSPRNG at run time and record that they did.

Site-based waiting list

A separate waiting list for a specific property, as opposed to one agency-wide list. Agencies with site-based lists run more, smaller lotteries, and each one needs its own complete record.

System of selection

The phrase federal rules use for what an agency's written policy must state: how applicants are chosen from the waiting list. A lottery is a system of selection; so is date-and-time order. The compliance obligation is not the method: it's the match between the written policy and the practice.

T

Tamper-evident record

A record that carries proof of its own integrity: a signature computed from the data itself, such that altering any character anywhere produces a different signature. Tamper-evidence does not prevent alteration; it makes alteration detectable, which for evidentiary purposes is the property that matters. The full argument is in How to Document a Housing Lottery So It Survives a Challenge.

Tenant selection plan (TSP)

The written selection policy for an individual property, standard in LIHTC and other multifamily programs: the property-level counterpart of an ACOP or administrative plan. A lease-up lottery must match the TSP the same way a waitlist lottery must match agency policy.

Ticket number

A neutral identifier assigned to each entry so that results can be published and verified without exposing applicant identity. The applicant knows their own number; the public list shows numbers and positions only. Simple, and it solves most of the results-publication privacy problem.

V

Verification (of results)

The ability of someone outside the process (an auditor, a board member, an applicant) to confirm that published results are the results the drawing produced. Verification is what separates trust us from check for yourself, and it's the property the entire documentation apparatus exists to create.

Voucher

The subsidy commitment an HCV household receives when selected from the waiting list and found eligible, which it then uses to lease a private-market unit. The lottery decides when a household is reached; the voucher is what being reached eventually yields.

W

Waiting list (waitlist)

The ordered list of applicant households from which a program fills vacancies. The order is the asset (it determines who gets housed and when), which is why how the order was created, and whether it has changed since, are the questions that matter.

Waitlist opening

The event of a closed list accepting applications again: public notice, an application window, and (when oversubscribed, which is nearly always) a lottery to order the entries. The full sequence is in Opening a Closed Waiting List: A Practical Checklist.

Weighted lottery

A lottery in which some entries carry better odds than others (a household with a preference might hold three chances to another's one), but no entry is guaranteed to order ahead of any other. Contrast preference tier, which is an absolute ordering. An agency's policy must be explicit about which design it uses; the two produce very different lists from identical pools.

Weighting

The general practice of giving entries unequal probability in a drawing. Weighting decisions are policy decisions with fair housing implications, and they belong in the written policy in exact terms: "veterans receive additional weight" is not a policy; "entries from veteran households are entered three times" is.

Acronym decoder

Definitions summarize common usage and general federal rules; your program's governing documents and counsel control.