Decoy list¶

A coordinated party-list strategy that separates constituency and list candidacies to evade compensatory seat linkage in mixed-member elections.

Version: v2 · 2026-09-19 · History
Domain-specific #: 4065
Domain group: Social Sciences
Origin domain: Political Science
Subdomain: Electoral Systems → Political Science

Core Idea¶

A party places local candidates under a formally distinct list while directing party votes to its main list, so constituency wins are not deducted from compensatory list entitlements as intended. Nominal organizational separation breaks the identity link used by the allocation formula, converting a compensatory mixed system toward parallel outcomes and generating extra seats. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.

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The Split-Team Trick

Imagine a game where teams that win fewer races get bonus points, so things stay fair. One team secretly splits in two with different names: one runs the races and one collects the bonus. Because the rules think they're different teams, the race wins don't cut the bonus, and the team gets extra points. In elections, that trick is called a decoy list.

Splitting a Party to Get Extra Seats

Some countries elect lawmakers in two ways at once: people vote for a local candidate and also for a party. The extra seats from the party vote are handed out to balance things, so a party that already won lots of local seats gets fewer extra seats. A decoy list is a trick where a party puts its local candidates under a separate list with a different name, while telling voters to give their party vote to the main list. On paper they look like two different groups, so the local wins are not subtracted from the main list's extra seats. The party ends up with more seats than the balancing rules meant it to have.

Compensation-Evading Split List

A decoy list is a tactic in mixed electoral systems that are designed to be compensatory: list seats are allocated to make up for constituency results, so a party's constituency wins are deducted from its list seat entitlement. A party runs its constituency candidates under a formally separate list or party while urging voters to give their list votes to the main party. Because the allocation formula links compensation to party identity, this nominal split breaks the link, so constituency wins aren't subtracted. The system then behaves more like a parallel system, and the coordinated parties win extra seats. Confirming a decoy list means checking that the law ties compensation to party identity, that coordinated lists split that identity across the two vote tiers, and comparing with how seats would have been allocated without the split.

A decoy list is a strategic manipulation of compensatory mixed-member electoral systems. In these systems, the list tier compensates for disproportionality in the constituency tier: each party's list entitlement is computed from its party vote, and its constituency wins are deducted. The deduction depends on the law identifying the constituency candidates and the list as the same party. A party can create a formally distinct list to hold its local candidates while directing its supporters' party votes to its main list. The nominal organizational separation breaks the identity link used by the allocation formula, so the main list receives full compensation while the decoy retains the constituency seats, converting the system's outcome toward that of a parallel (non-compensatory) system and yielding extra seats. Establishing a decoy list requires three things: that the electoral law ties compensation to party identity, that coordinated lists split that identity across vote tiers, and a counterfactual allocation computed as if the split had not occurred.

Scope of Application¶

Decoy list belongs to electoral systems and is useful where the analyst can specify the typed electoral systems carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, then evaluate the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated. The scope is broad within that domain but bounded by the need for the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated. Descriptive electoral-system analysis only; legality and terminology vary by jurisdiction and this is not campaign advice.

Clarity¶

The abstraction clarifies a crowded vocabulary by making the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test. A bare label is insufficient because the name Decoy list can be used for a formal identity, an implementation, or a neighboring result unless carrier and convention are stated.

Manages Complexity¶

Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to Decoy list. Decoy list compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.

Abstract Reasoning¶

Identify the carrier. State what the elements, states, objects, or observations are: the typed electoral systems carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets. Reject examples whose alleged carrier belongs to a different problem.
Lock the constitutive rule. Express the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated independently of one notation or implementation.

Knowledge Transfer¶

Knowledge transfers strongly among subfields of electoral systems because they reuse the typed electoral systems carrier, defining objects and relations, parameters, conventions, evidence, boundary cases, and comparison targets, Nominal organizational separation breaks the identity link used by the allocation formula, converting a compensatory mixed system toward parallel outcomes and generating extra seats., and type the carrier, state every parameter and convention in the definition, test that the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.

Relationships to Other Abstractions¶

Current abstraction Decoy list Domain-specific

Parents (1) — outgoing typed relations

Decoy list is a kind of Mechanism Design Prime

What makes it its own entry: the domain-specific identity determined by the electoral law links compensation to party identity, coordinated lists split that identity across vote tiers, and the counterfactual allocation without the split is evaluated.

Hierarchy path (1) — routes to 1 parentless root

Decoy list → is a kind of Mechanism Design

Neighborhood in Abstraction Space¶

Decoy list sits in a crowded region of the domain-specific corpus (30^th percentile for distinctiveness): several abstractions share nearly its structure, so a description that fits it tends to fit its neighbors too.

Family — Political Power, Governance & Legitimacy (17 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-25