Reference library · Media planning
Frequency
Frequency is the average number of times a reached person was exposed to the campaign within the measurement period, calculated as total exposures divided by the number of people reached (not the total target population). It tells the planner how deep the message landed on those it landed on, separate from how wide the campaign spread.
Formula
Worked example
A campaign targets 2,000,000 adults 25-54 in a mid-size market. It delivers 450 GRP and reaches 60% of the target (1,200,000 people), meaning total impressions = 9,000,000. Frequency = 450 GRP ÷ 60% = 7.5, or equivalently 9,000,000 impressions ÷ 1,200,000 reached = 7.5. The plan is delivering 7.5 exposures per reached person on average, well above a typical 3+ effective frequency threshold, so the planner can shift weight toward extending reach instead of adding more spots.
How it is used
Planners track frequency against an effective-frequency target (often 3+ for awareness, higher for complex messages) to judge whether the campaign is under-exposing or over-exposing the audience it has already reached. Mid-flight, a frequency that is climbing while reach has plateaued signals it is time to shift GRPs to new dayparts, placements or channels rather than keep pressing the same audience. The mistake is treating the average as if every reached person got exactly that many exposures.
The common mistake
Frequency is a mean, not a uniform delivery: a 7.5 average can hide a distribution where half the reached audience saw the ad once and a smaller group saw it twenty times, so pair it with a frequency distribution or reach curve before concluding the plan is well calibrated.