Methodology

How we collect, process, and present federal lobbying data from 726,000+ Senate LDA filings.

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Data Source

All data comes from the Senate Lobbying Disclosure Act (LDA) API, which provides machine-readable access to all lobbying registrations and quarterly activity reports filed since 1999.

Our dataset covers 2018–2025, comprising 726,000+ filings with a total of $37.7 billion in reported lobbying income/expenses.

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Data Collection

We pull all filings from the Senate LDA API in annual batches. Each filing includes:

  • Client name, state, and description
  • Lobbying firm name
  • Individual lobbyist names and former government positions
  • Issue categories (79 LDA-defined codes)
  • Reported income or expenses
  • Foreign entity affiliations
  • Filing type (registration or quarterly report)
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Processing Pipeline

Raw filings are processed into aggregated datasets:

Client aggregation
Total spending, yearly trends, associated firms and lobbyists
Firm aggregation
Total income, client lists, lobbyist rosters
Lobbyist profiles
Filing counts, client coverage, government positions
Issue analysis
Spending by issue code, yearly trends, top clients per issue
State analysis
Spending by client headquarters state
Revolving door
Lobbyists who disclosed prior government positions
Foreign entities
Non-US entities disclosed in lobbying filings
Text analysis
Word frequency and bill mention extraction from descriptions
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Influence Score

Our composite Influence Score combines five dimensions:

  1. Spending: Total lobbying expenditure
  2. Lobbyist count: Number of individual lobbyists deployed
  3. Revolving door: Former government officials on the team
  4. Issue breadth: Number of different issue categories lobbied on
  5. Longevity: Years of continuous lobbying activity

Each dimension is normalized using a power curve (exponent 0.35) against the maximum in the dataset, then averaged into a 0–100 score.

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ROI Calculation

The Lobbying ROI Calculator cross-references lobbying spending with government contract data from USASpending.gov. ROI is calculated as: (Total Contracts Received) / (Total Lobbying Spent). This is correlational, not causal — lobbying doesn't guarantee contracts.

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Limitations

  • LDA filings are self-reported by lobbyists. Accuracy depends on filer compliance.
  • Income/expense amounts are often rounded or estimated.
  • Some filings report $0 income (amendment or termination filings).
  • Our entity matching (for ROI) uses name similarity and may have false positives/negatives.
  • This is journalism, not legal accusation. Being a top spender doesn't imply wrongdoing.
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Open Data

All processed data is freely available on our Downloads page. We encourage journalists, researchers, and citizens to use it for their own analysis.

Data Sources: Senate LDA Filings (lda.senate.gov) · USASpending.gov (contract data) · Lobbying Disclosure Act Reports

Last updated: February 2026

This site is an independent journalism project. Analysis and editorial content are not affiliated with or endorsed by any government agency.