Measurement

Reach

unique reach

Definition

Reach is an estimate of unique people who could have seen the coverage, as opposed to raw impressions which reuse the same eyes. In digital you can sometimes get unique cookies or logged-in users. In print and broadcast you are back to kits and diaries.

The word is abused. “We reached 40 million” usually means someone summed unique visitor numbers across outlets that share readers.

How it works

Deduplicate when the tool can. If it cannot, say “unduplicated unknown” and report outlet uniques as a range, not a sum. Pair with a quality cut: in-target vs anyone.

Worked example

Three overlapping tech sites, 2.1M, 1.8M, and 900k uniques. Sum = 4.8M impressions-as-uniques. A panel study guesses 35% overlap. Report ~3.1M potential unique reach, with the method, or don’t sum them.

How it differs

Impressions count opportunities, including repeats. Referral traffic is observed visits. Reach is unique people, estimated.

Common errors

Summing unique visitors across 50 outlets. Using Facebook page reach for a press hit. Mixing paid reach into earned.

Sources