Reference library · Media planning
Effective Reach (3+)
Effective reach (3+) is the percentage of the target audience exposed to a campaign at least three times during the measurement period, on the premise that fewer exposures are too weak to register or persuade. It excludes light contacts of one or two exposures from the reach figure the plan is judged on.
Formula
Worked example
Target universe: adults 25-54 in the Czech Republic, 3,500,000 people. A 4-week campaign delivers 250 GRPs. The panel-modeled reach curve shows Reach(1+) = 62% (2,170,000 people) and Reach(3+) = 34% (1,190,000 people). So effective reach is 1,190,000 people, or 34% of the universe, and only 55% of everyone the campaign technically reached actually hit the 3+ threshold; the rest were reached once or twice.
How it is used
Planners set the frequency threshold before optimizing the plan, then choose the channel mix and flighting pattern that maximizes population above that threshold rather than maximizing gross reach or average frequency alone, since a reach curve is always skewed toward light exposure. The recurring mistake is reading average frequency off the plan (e.g. "3.2") and assuming most of the audience is therefore effectively reached, when in fact a small heavy-viewing segment can pull the average up while half the reached audience sits at 1 or 2 exposures.
The common mistake
Average frequency at or above the threshold does not mean effective reach is high; check the frequency distribution, not the average, because exposure is never spread evenly across the audience.