See the timing technique mentioned above. If you are tracking customer transactions, you can compare those transactions to your PR efforts over time. If PR is the only way you are getting messages out there during a specific time, then sales changes are probably related to PR changes. For example, Sears launched a new line of fashion footwear with one story in The New York Times. There was no other information out there about the footwear at the time, so the jump in sales could only be attributed to the PR effort. You need to be working closely with other communications and marketing groups if you want to isolate PR results from other activities. -KDP