Methodology

Every number displayed on this site is computed from a transparent formula and traceable to the underlying data. This page lists every methodology currently in use across the platform, with the version of the formula, what is included, what is excluded, and known limitations.

Methodologies are versioned. The score you see today carries the version of the formula used to compute it. When a methodology is improved, the new version replaces the old, and affected metrics are recalculated.

Key figures, defined

These terms mean different things and are never used interchangeably on this site.

Seats

The official number of seats allocated to a country or held by the Parliament as a whole (720 for the 2024–2029 term). A fixed, constitutional figure.

MEPs this term

Distinct people who have held a seat during the current term — including replacements. This is higher than the number of seats wherever an MEP resigned and was replaced mid-term.

MEPs in a political group

MEPs currently affiliated to a European political group. Lower than the seat count where members sit as non-attached or are not yet assigned.

Vote participants

MEPs eligible to vote at the moment of a specific roll-call. Varies vote by vote.

Recorded positions

The total number of individual MEP positions across all roll-call votes (For, Against, Abstention, Did not vote). Many millions in aggregate.

Example: France holds 81 seats; 82 MEPs served during the term because one seat changed hands. We show this as “81 seats · 82 this term”, never “82 of 81”.

Co-signature / Co-authorship Network

cosignatures

Counts how often two MEPs appear as authors on the same parliamentary document or question.

edge_count(A,B) = count(distinct documents where A and B both have participation role AUTHOR)

Delegation Cohesion

delegation-cohesion

How unified a country's delegation is across all roll-call votes.

cohesion = average over votes of (majority_position_count / expressed_positions_count)

Group Loyalty

group-loyalty

How often a MEP votes with the majority position of their European political group.

group_loyalty = votes_matching_group_majority / eligible_expressed_votes

MEP Attendance

attendance

Share of eligible roll-call votes where the MEP cast a position (For, Against or Abstain).

attendance = votes_cast / total_eligible_votes

MEP Similarity

similarity

How often two MEPs cast the same expressed position across votes where both were present.

similarity = same_position_votes / comparable_expressed_votes

National Delegation Alignment

delegation-loyalty

How often a MEP votes with the majority position of their national delegation (MEPs from the same country).

delegation_loyalty = votes_matching_delegation_majority / eligible_expressed_votes

Topic Classification (rule-based)

topic-rules

Assigns one primary and up to 3 secondary topics per vote using keyword rules, concept mappings, and country detection.

confidence = min(0.98, 0.45 + min(0.4, total_weight × 0.18) + min(0.15, evidence_count × 0.05))

Vote Importance Score

importance

Prioritisation indicator (0–100) combining 8 transparent factors per vote.

score = vote_type + legislative + topic + group_division + country_division + close_vote + turnout + rebel_votes; score = min(100, score)

Why this matters

Public-interest data tools must be auditable. Every score on this platform can be traced back to its formula, the input data, and the version of the methodology used. Where applicable, scores carry a "Why this number?" link that opens the audit detail for that specific value.

Data sources are the European Parliament's official roll-call records. The platform's code is open source under MIT; data is published under ODC-By 1.0; analytical content under CC-BY 4.0.