Voting Strategies¶

Voting strategies aggregate NegotiationVote inputs into an AggregatedScore for Negotiation Room decisions and other consensus workflows. Pair a strategy with VotingAggregator to compute statistics and produce a weighted outcome.

Source: sdks/py_sdk/sw4rm/voting/strategies.py

Strategy Summary¶

AggregationStrategy Protocol¶

All strategies implement a shared protocol:

from typing import Protocol
from sw4rm.negotiation_types import AggregatedScore, NegotiationVote

class AggregationStrategy(Protocol):
    def aggregate(self, votes: list[NegotiationVote]) -> AggregatedScore:
        ...

All implementations raise ValueError when votes is empty.

Strategy Details¶

SimpleAverageAggregator¶

• Constructor: SimpleAverageAggregator()

• aggregate(votes) behavior: Computes mean, min, max, std dev from scores and sets weighted_mean to the same value as mean.

• Edge cases: Empty vote lists raise ValueError.

ConfidenceWeightedAggregator¶

• Constructor: ConfidenceWeightedAggregator()

• aggregate(votes) behavior: Computes the unweighted statistics and sets weighted_mean = sum(score_i * confidence_i) / sum(confidence_i).

• Edge cases: If the total confidence is zero, weighted_mean falls back to the simple mean. Empty vote lists raise ValueError.

MajorityVoteAggregator¶

• Constructor: MajorityVoteAggregator()

• aggregate(votes) behavior: Uses the pass/fail majority to set weighted_mean and still computes the unweighted statistics from scores.

• Score mapping:

• All passed: 10.0

• Majority passed (>50%): 7.5

• Tie: 5.0

• Majority failed (>50%): 2.5

• All failed: 0.0

• Edge cases: Empty vote lists raise ValueError.

BordaCountAggregator¶

• Constructor: BordaCountAggregator()

• aggregate(votes) behavior: Ranks scores from highest to lowest, assigns points n..1, averages the points per vote, and normalizes to a 0..10 weighted_mean. Unweighted statistics are still computed from scores.

• Edge cases: Empty vote lists raise ValueError. Ties are resolved by the input order of votes during ranking.

Using Strategies in a Negotiation Room¶

from sw4rm.negotiation_types import DecisionOutcome, NegotiationDecision, NegotiationVote
from sw4rm.voting import VotingAggregator, ConfidenceWeightedAggregator

votes = [
    NegotiationVote(
        artifact_id="artifact-123",
        critic_id="critic-1",
        score=8.5,
        confidence=0.9,
        passed=True,
        strengths=["Clear intent"],
        weaknesses=["Missing tests"],
        recommendations=["Add unit tests"],
        negotiation_room_id="room-1",
    ),
    NegotiationVote(
        artifact_id="artifact-123",
        critic_id="critic-2",
        score=6.5,
        confidence=0.6,
        passed=False,
        strengths=["Readable code"],
        weaknesses=["No validation"],
        recommendations=["Add input checks"],
        negotiation_room_id="room-1",
    ),
]

aggregator = VotingAggregator(ConfidenceWeightedAggregator())
aggregated = aggregator.aggregate(votes)

if aggregated.weighted_mean >= 7.0 and aggregator.detect_consensus(votes):
    outcome = DecisionOutcome.APPROVED
    reason = "High confidence consensus"
else:
    outcome = DecisionOutcome.REVISION_REQUESTED
    reason = "Consensus threshold not met"

decision = NegotiationDecision(
    artifact_id="artifact-123",
    outcome=outcome,
    votes=votes,
    aggregated_score=aggregated,
    policy_version="1.0",
    reason=reason,
    negotiation_room_id="room-1",
)

Strategy Selection Guide¶

Related Documentation¶

• Negotiation Room Client
• Advanced Patterns