Contact research
Deduplicate business contacts with OpenRefine
Clean a research file without losing source notes, opt-outs or distinct people at the same company.
Duplicate contacts create repeated work and sometimes repeated messages. OpenRefine can help inspect a messy file, but the merge rules need human judgment. Two rows with similar names are not always the same person, and two contacts at one company may both be legitimate records.
Work on a copy and preserve the original exports. Decide which fields identify a record, which fields may be combined and which exclusions must always survive. Do this before clicking a cleanup command.
Clean the file deliberately
- 1
Import only needed fields
Keep the contact route, organization, source URL, checked date and status. Leave sensitive notes out of the cleanup project if they do not serve the task. Run the tool on an approved machine.
- 2
Inspect with facets
Use text facets to find inconsistent status labels and blank values. Review suspicious groups before changing them. A label such as do not contact should not become active because another export uses a different spelling.
- 3
Normalize safe differences
Trim surrounding spaces and standardize your own status vocabulary. Be careful with names and email local parts. Do not remove punctuation or merge aliases merely because they look similar.
- 4
Review candidate duplicates
Use exact matching on an appropriate identifier first. Compare source and date when records conflict. Keep different people at the same company separate, and preserve the stronger exclusion when a contact has opted out.
- 5
Export and reconcile
Save the cleaned file and a note explaining the merge rules. Compare before-and-after counts and spot-check non-English names. Import only the reviewed records into the destination workflow.
| Pair of records | Recommended review |
|---|---|
| Same address, different checked dates | Keep history and assess the newer source |
| Same company, different people | Keep separate unless evidence proves duplication |
| Same contact, active and opted out | Preserve the opt-out |
| Similar names, different domains | Do not auto-merge |
OpenRefine is free, and its facets make groups easier to inspect. The result is a cleaner dataset, not a verified mailing list. Keep research-only contacts out of Venmail broadcasts unless they separately qualify for that audience.
For legitimate correspondence, use the cleaned record to avoid repeated work and keep one owner for the conversation. If someone asks not to be contacted, update the central exclusion record before the next export so the request does not get lost between tools.
Before importing
- Original data is preserved
- Merge rules are documented
- Distinct contacts remain distinct
- Exclusions survive
- Counts and sample records reconcile
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