Independent public-data directory · Tamil Nadu election data

Analytics Methodology & Data Integrity

Mathematical definitions, Form 20 reconciliation protocols, clustering confidence tiers, and ecological fallacy guardrails for Polldata.

Evidence-First Analytics Standards

Public-interest election statistics designed to answer analytical questions without speculation.

Polldata presents official polling-station data sourced from published Election Commission of India (ECI) Form 20 Final Result Sheets. All analytical indicators, distribution curves, and locality groupings are computed deterministically using standard mathematical formulations.

Core Methodological Principles

1. Evidence Before Interpretation

Every narrative insight or ranking is tied directly to underlying Form 20 counts. No speculative scores, persuasion models, or machine-learning voter estimates are used.

2. Context Before Ranking

No booth or locality is presented as "strongest" or "worst" without its total denominator (N booths) and the constituency baseline median.

3. Exact vs. Estimated Separation

Form 20 vote counts are exact aggregate counts. Geographic boundary approximations and locality clusters are labeled with explicit confidence tiers.

4. Non-Attribution of Demographics

Electoral Roll demographic data (age bands, gender) are kept strictly separate from voting returns. Ballot secrecy is absolute under Indian law.

Formula Reference

Lead Margin (Percentage Points)Margin = Share(Winner) - Share(RunnerUp)

Calculated in percentage points (pp) rather than raw percentages to ensure comparability across booths with varying turnout.

Relative Position (Constituency Percentile)Percentile = (Count(Booths ≤ BoothShare) / N) × 100

Measures where a candidate's vote share falls within the constituency's distribution. A 90th percentile result indicates the party outperformed 90% of polling stations in that AC.

Median Booth MarginMedian(Margins(Booth 1 .. Booth N))

The 50th percentile of victory margins across all stations in an AC. Preferred over the arithmetic mean because it is resilient to extreme blowout outlier booths.

Close Contests BenchmarkCount(Booths where Margin ≤ 5.0 pp)

Identifies localized swing zones where a minor shift of fewer than 25 to 50 votes would have altered the station outcome.

Ecological Fallacy Guardrail Policy

The ecological fallacy occurs when inferences about the behavior of individual voters are deduced solely from aggregate statistics of the polling station.

✓ Acceptable phrasing:"Polling stations with higher voter turnout coincided with higher margins for Party A."
✗ Prohibited claim:"Young voters in this neighborhood voted for Party A."

Form 20 Provenance & Verification

Form 20 is the statutory return prescribed by Rule 56C(2) of the Conduct of Elections Rules, 1961, recording votes cast at each polling station in an Assembly Constituency.

Editorial & Corrections Policy →|Statewide Voter Patterns Dashboard →

Figures are presented for public information and may change as official records are corrected or updated.