Ma Data Extraction

⚠️ Default approach: Run web-based extraction FIRST, then use PDFs only for gaps.

Phase 1: Web-Based Extraction (Default — Run First)

1. Define a data dictionary that covers outcomes, covariates, and study identifiers.
   • Write to 05_extraction/data-dictionary.md (use references/data-dictionary-template.md)
2. Initialize a normalized SQLite database using scripts/init_extraction_db.py via uv run.
   • Use scripts/init_extraction_db.py
   • Creates 05_extraction/extraction.sqlite
3. Run WebSearch extraction for ALL included studies — see WebSearch Extraction (Default) below.
   • Read from 03_screening/round-01/included.bib or 04_fulltext/manifest.csv
   • This fills 70-80% of data fields automatically from PubMed, ClinicalTrials.gov, etc.
   • Tag all web-sourced values with [web] in the notes column
   • Write to 05_extraction/extraction.sqlite (studies table)
4. Review confidence scores: flag studies/fields with confidence < 0.7.

Phase 2: PDF-Based Extraction (Only for Gaps)

5. For studies with low-confidence fields, run scripts/llm_extract.py via uv run on available PDFs.
   • Use scripts/llm_extract.py
   • Read PDFs from 04_fulltext/*.pdf
   • Write to 05_extraction/llm_suggestions.jsonl
6. Extract remaining data with double-entry or verification where possible.
   • Update 05_extraction/extraction.sqlite
7. Record unit conversions and assumptions in 05_extraction/extraction-log.md.
   • Write to 05_extraction/extraction-log.md
8. Export a tidy CSV for analysis and lock the database snapshot.
   • Export 05_extraction/extraction.csv from SQLite
9. (Recommended) Record source references in 05_extraction/source.csv and validate with scripts/validate_sources.py.
   • Write to 05_extraction/source.csv (use references/source-template.csv)
   • Validate with scripts/validate_sources.py → 05_extraction/source_validation.md

Resources

• scripts/init_extraction_db.py initializes a standard extraction schema.
• scripts/llm_extract.py provides LLM-assisted extraction suggestions.
• scripts/validate_sources.py validates extraction vs source references.
• references/data-dictionary-template.md provides a dictionary scaffold.
• references/study-map-template.csv maps record_id to study_id if needed.
• references/source-template.csv for source references. Note: llm_extract.py requires a PDF parser such as pdfplumber or pypdf (install via uv add).

WebSearch Extraction (Default)

⚠️ This is the DEFAULT first step — Claude Code should run this BEFORE attempting PDF-based extraction. No scripts or API keys required.

When to Use

• ALWAYS — run as Phase 1 for every extraction workflow
• Fills 70-80% of fields from structured online sources
• Identifies exactly which studies need PDF follow-up

Procedure

1. Identify gaps: Scan extraction.csv for NULL or empty cells in critical columns (e.g., n_total, events_intervention, events_control, mean, sd).
2. Search per study: For each study with gaps, run WebSearch with the query pattern:
   • "<first_author> <year> <journal> <intervention> <outcome> results" or
   • "<DOI>" or "PMID:<pmid> abstract"
3. Fetch structured sources: Use WebFetch on high-value URLs:
   • PubMed abstract: https://pubmed.ncbi.nlm.nih.gov/<pmid>/
   • ClinicalTrials.gov: https://clinicaltrials.gov/study/<nct_id>
   • Europe PMC: https://europepmc.org/article/MED/<pmid>
4. Extract and fill: Read the returned content, extract the missing values, and update extraction.csv.
5. Tag provenance: For every web-filled value, append [web] in the notes column (e.g., n_total from PubMed abstract [web]).
6. Log in extraction-log.md: Record which studies/fields were filled via web search, with source URLs.

Confidence Rules

Limitations

• Cannot access paywalled full-text content via WebFetch
• Event counts by subgroup are rarely in abstracts
• Risk-of-bias details require full Methods section
• Always cross-check web-filled values if PDFs become available later

Validation

• Run consistency checks on missingness, ranges, and duplicated entries.
• Reconcile any discrepancies between double entries before analysis.
• Validate source coverage with scripts/validate_sources.py when sources are available.

Pipeline Navigation