Eligibility Design Failure Modes

Purpose

This page identifies recurring structural failure patterns that arise from the design of eligibility rules themselves. These failures occur at the level of rule construction and counting logic, independent of downstream system behavior or normative evaluation.

The terms on this page classify how eligibility rules misallocate counting, exemption, or qualification in ways that produce unequal or unstable application over time. These definitions support analysis across the Framework, including Structural Validity (Module I), Normative Adequacy (Module II), and comparative case evaluation.

Prior-Service Qualification

Definition
A structural failure mode in which prior service functions as a qualifying condition for exemption from otherwise uniform eligibility limits

Structural Characteristics

• Eligibility differs based on service history at the moment of adoption

• Prior service determines whether counting applies

• Incumbents or defined cohorts receive durable or permanent exemption

• The eligibility rule operates on persons rather than uniformly on service

Structural Effect
This failure mode converts service history into a qualification for exemption, resulting in asymmetric eligibility over time.

Illustrative Patterns

• Incumbent Exemption — incumbents at adoption remain eligible while future entrants are bound

• Exempt-Class Expansion — the protected class grows through appointment, succession, or requalification pathways

• Service-History Laundering — prior service is excluded from counting through definitional or temporal manipulation