12.2 Group Underwriting and Contribution/Participation
Key Takeaways
- Contributory plans require at least 75% participation; noncontributory (employer-pays-all) plans require 100%.
- Experience rating uses the group's own claims history; community/manual rating uses pooled regional or industry data.
- Larger groups are credible enough for experience rating; small groups are community-rated.
- Minimum participation rules exist to keep healthy members in the pool and limit adverse selection.
Group underwriting evaluates the entire group's risk, not individual members. The underwriter looks at group size, industry, age and gender distribution, prior claims, geographic location, and the stability and purpose of the group. The two levers that control adverse selection are participation requirements and rating method.
Contributory vs. Noncontributory Plans
Who pays the premium drives how many members must enroll.
| Plan Type | Who Pays Premium | Minimum Participation |
|---|---|---|
| Noncontributory | Employer pays 100% | 100% of eligible employees |
| Contributory | Employee shares the cost | At least 75% of eligible employees |
In a noncontributory plan the employer pays the full premium, so all eligible employees must be covered — there is no opt-out and therefore no chance for only the unhealthy to join.
In a contributory plan employees pay part of the cost, so some will decline. To stop only sick employees from electing coverage, insurers require a minimum of 75% participation of eligible employees. (Some plans express this differently, but 75% is the standard exam answer.)
Worked Participation Example
Suppose a contributory plan covers a firm with 80 eligible employees. The insurer requires 75% participation.
- Required enrollees = 80 x 0.75 = 60 employees.
- If only 54 enroll, participation = 54 / 80 = 67.5% — below the 75% minimum, so the insurer can decline or re-rate the group.
- The firm must enroll at least 6 more employees (60 - 54) to qualify.
Now assume the plan converts to noncontributory (employer pays 100%). All 80 must be covered; participation must equal 100%, or 80 employees. The shift from contributory to noncontributory raises the participation bar from 60 to 80 employees but eliminates employee opt-outs entirely.
Why the Math Matters on the Exam
Questions often give a head count and a plan type and ask for the minimum number who must enroll. Multiply eligible employees by 0.75 for contributory plans; use the full count for noncontributory plans.
A contributory group health plan has 120 eligible employees. What is the minimum number who must participate?
Rating Methods: How Premiums Are Set
Group premiums are set with one of two broad approaches, chosen mainly by group size and credibility (how statistically reliable the group's own data is).
- Community rating / manual rating — the insurer charges a rate built from pooled data for a region, industry, or block of business. The individual group's claims do not change the rate. Used for small groups (commonly under 50 lives) whose own data is too thin to be credible. The ACA requires small-group and individual rates to be community-rated with only limited adjusters (age, geography, tobacco, family size).
- Experience rating — the insurer adjusts the group's premium up or down based on that group's own claims history. Used for large groups whose volume makes their data credible. A group with favorable claims earns lower renewals; a group with high claims pays more.
| Group Size | Typical Rating Method | Credibility |
|---|---|---|
| Small (under 50) | Community / manual | Low |
| Medium (50-500) | Blended | Moderate |
| Large (500+) | Experience | High |
Renewal and Re-Rating Considerations
Because group coverage is guaranteed issue, the insurer protects itself at renewal rather than at entry. For an experience-rated group, a year of heavy claims directly raises next year's premium. For a community-rated small group, the insurer cannot single out one group's claims, so it raises the entire community pool or uses allowed adjusters.
The practical exam point: a large employer with a healthy workforce benefits from experience rating (lower premiums reward good experience), while a small employer with a few catastrophic claims is shielded by community rating because its losses are spread across the pool. Match the rating method to group size and credibility, and remember that participation minimums (75% contributory, 100% noncontributory) are the entry-side defense while rating is the renewal-side defense.
Which rating method bases a group's premium on its own claims history and is used mainly for large groups?
Underwriting Factors and Group Stability
Beyond participation and rating method, the group underwriter weighs several characteristics that predict future claims:
- Group size — larger groups are more predictable and more credible for experience rating.
- Age and gender distribution — an older workforce raises expected claims.
- Industry and occupation — hazardous industries (mining, construction) carry higher morbidity than office work.
- Group purpose and stability — long-established groups with low turnover are favorable; rapidly changing or newly formed groups invite anti-selection.
- Prior claims experience and prior carrier history — a pattern of high claims or frequent carrier changes is a red flag.
- Geographic location — regional cost and utilization vary.
The Underwriting Trade-Off
Group underwriting accepts the loss of individual medical selection in exchange for volume and predictability. The larger and more stable the group, the less the insurer worries about any one sick member, because the law of large numbers makes total claims predictable. This is why minimum-participation rules (75% contributory, 100% noncontributory) matter so much: they guarantee the pool is large and representative rather than skewed toward the unhealthy.
A small group that barely clears 75% with mostly older, high-claim members may still be declined or heavily re-rated despite meeting the participation floor, because the underwriter judges the whole risk picture, not the percentage alone.