List deduping

  1. Get all of your various list sources into a series of spreadsheets or worksheets in a single spreadsheet
  2. Rename columns and arrange their order so that they are identical between sources
  3. Create a new spreadsheet or worksheet to hold the deduped list in case you need to revert to the originals for any reason
  4. copy all of the data into this new spreadsheet
  5. Insert a new column called 'dedupe data'
  6. enter the following formula in your dedupe data cell for the first row of data and copy it to all rows that have names {=firstname&lastname&company} - where 'firstname' and the other cell names would be replaced with the cell reference (e.g. =A2&B2&C2 if that's where those data live for that particular row)
  7. Sort all your contacts by 'dedupe data'
  8. create another column called 'dedupe check' and enter the following formula there: {=if(D3=D2,"Dupe",""} (assuming your dedupe data column was column D and the first row of data was row 2 in this example).
  9. You have just created a simple flag for possible duplicates. Investigate each instance of 'Dupe' and decide if it is indeed a duplicate and whether to modify one before deleting one of the duplicates. Note that when you delete a row of data you might get your references in your formula a bit twisted and need to tidy them up.