Waiting Period¶

Timing policy — instantiates Adverse Selection Filtering

Imposes a delay between joining and full benefit eligibility so entrants who join specifically to cover an imminent, already-known need can't do so under pooled terms.

A Waiting Period filters a pool on the one dimension its siblings mostly ignore: time. By inserting a delay between joining and full benefit eligibility, it targets the hidden type that adverse selection is often sharpest with — the entrant who buys in precisely because they already know a large claim is coming, intending to collect and leave. Its distinctive move is that it neither prices, screens, nor excludes; it simply makes just-in-time entry unprofitable, so the imminent-need type self-deselects while ordinary entrants, who join before they need anything, are barely affected. The filter is the clock.

Example¶

Dental insurance illustrates it cleanly. Someone who knows they need a $2,000 crown has every incentive to buy coverage the month before the work and drop it after — a move that, repeated across a pool, means the plan pays out far more than premiums assume. A waiting period removes the incentive: major services like crowns and orthodontics aren't covered until the enrollee has been in the pool for, say, ≈6–12 months, while routine cleanings may carry no wait at all. An enrollee genuinely planning ahead is unbothered; the enrollee trying to time entry to an imminent, already-known need finds the delay makes it pointless. The pool's composition is protected not by asking anyone about their teeth but by making the calendar do the sorting.

The delay is deliberately blunt on the time axis — it also postpones coverage for an honest newcomer with a legitimate immediate need, which is why its length has to be proportioned to the timing risk rather than maximized.

How it works¶

Delay benefit eligibility. Coverage for the targeted benefit does not begin until the entrant has been in the pool for a set period, so entry cannot be timed to an imminent claim.
Scope by benefit category. The wait attaches to the categories most exposed to just-in-time selection (major or elective work), while low-selection benefits stay immediately available.
Make the wait bite the imminent-need type. Because the delay costs almost nothing to someone with no near-term need and everything to someone timing a known claim, it separates the two without any interrogation.
Waive where selection risk is absent. Continuous prior coverage or similar conditions can waive the wait, so it doesn't punish entrants who were never gaming the timing.

Tuning parameters¶

Length — how long the delay runs. Longer deters more just-in-time entry but postpones coverage for legitimate immediate needs.
Covered categories — which benefits carry a wait; broad scope catches more selection but harms more honest newcomers.
Waiver conditions — what excuses the wait (e.g., unbroken prior coverage), narrowing the filter to genuine timing risk.
Graded vs. cliff eligibility — whether benefits phase in over the period or switch on at the end.

When it helps, and when it misleads¶

Its strength is precision on the timing dimension and near-zero cost: it targets exactly the entrant who joins to cover an imminent, already-known need, is self-executing, and leaves the ordinary member untouched. It is the right tool where the hidden type expresses itself mainly as when someone chooses to enter.

Its central weakness is that it is blunt across time: it also delays coverage for honest new entrants whose need is simply immediate through no gaming of theirs, which can be genuinely harmful in health contexts. The classic misuse is stacking long waiting periods across many categories to collect premiums while deferring nearly all payout. The discipline that guards against this is to keep the period proportioned to the actual timing risk, waive it for continuous prior coverage, and never let it stand in for a denial of legitimate need — a reason health-insurance analogues like pre-existing-condition exclusions are restricted by law in many jurisdictions.^[1]

How it implements the components¶

Waiting Period realizes a narrow, time-based slice of the archetype:

term_adjustment_rule — the waiting period is a term of the offer, set on the time axis so that entry timed to a known imminent claim no longer pays.
hidden_type_selection_model — it specifically targets the imminent-need hidden type who times entry to a claim, letting that type self-deselect.

Its term is timing; the price term belongs to Risk-Adjusted Pricing and the self-selection cost-share to Deductible or Copay Schedule. It does not estimate an applicant's risk (Underwriting Review).

Instantiates: Adverse Selection Filtering — it filters on the time axis, deterring entrants who join to cover an imminent known need.
Sibling mechanisms: Deductible or Copay Schedule · Underwriting Review · Claims or Outcome Experience Rating · Minimum Eligibility Standard · Prequalification Process · Probationary Entry · Quality Certification Requirement · Risk Tier Assignment · Risk-Adjusted Pricing · Seller Rating or Quality Grading · Warranty or Guarantee Requirement

References¶

[1] A pre-existing condition exclusion is the adjacent, more contested timing device — withholding coverage for conditions present before enrollment. Because it can deny legitimate need rather than merely deter gaming, it is restricted or prohibited for health coverage in many jurisdictions, which marks the line a waiting period must not cross. ↩