Frequency

Frequency is the average number of times one person was shown your advert. It is worked out by dividing impressions by reach, and it is the metric most small businesses never open. It also explains the single most common story in paid social: an advert that performs well for two weeks and then quietly stops working.

In short

• Frequency is impressions divided by reach.
• It rises on its own when the audience is smaller than the budget.
• Rising frequency with falling results means the audience is finished.
• It is an average, so it hides the people who saw the advert many times.

How the number is built

Three metrics describe the same delivery from three angles, and reports mix them up constantly.

• Reach. How many accounts were shown the advert at least once.
• Impressions. How many times it was shown in total, repeats included.
• Frequency. Impressions divided by reach.

An advert with 12,000 impressions and 3,000 reach has a frequency of four. Each account it reached saw it four times on average. Whether four is sensible depends entirely on what you were doing, which is why the number means nothing without the objective sitting next to it.

One detail catches people out. Frequency is calculated over whichever date range you selected, so the same campaign has a different frequency this week and this quarter. Neither figure is wrong and they are not comparable. Pick a window, use it every time, and write it beside the number so nobody has to guess.

Why it climbs without anybody touching it

Frequency is not something you set. It is a consequence of three things you did set: how many people your targeting allows, how much you are spending, and how long the campaign has been running.

Once the platform has shown the advert to everybody your targeting permits, the remaining budget has nowhere else to go. It spends the money on the same people again. A narrow audience, a healthy budget and a campaign left running for two months will produce a high frequency on its own, without anything going wrong and without anybody making a decision.

This is why frequency usually looks fine in week one and uncomfortable in week six. Nothing changed except the arithmetic.

What it costs when it climbs too far

The damage arrives in a predictable order.

• Response falls first. The people most likely to act have acted. Everybody left has already declined, several times.
• Cost per result rises. You are paying the same to reach people who have already made up their mind.
• Negative feedback appears. Hiding the advert, reporting it, unfollowing the page. This is the point where the campaign starts costing you something that is not money.
• The account gets more expensive generally. Platforms price delivery partly on how people respond to your content, so an advert people are tired of makes the next one harder to deliver.

The order matters. By the time complaints show up, the response fell weeks earlier and nobody was looking.

There is no correct number

The right frequency depends on what the campaign is for.

A campaign introducing a business nobody has heard of needs repetition. Being seen once by ten thousand strangers achieves very little, and brand awareness work is one of the few cases where a higher frequency is the point rather than the problem.

A campaign promoting a one day sale is the opposite. Repetition inside a short window is how a promotion becomes an irritation.

Retargeting sits in the most awkward position. The audience can only ever be as large as the traffic your website received, so it is small by construction. A retargeting campaign will reach an uncomfortable frequency faster than any other campaign in the account, on a budget that looks modest on paper.

What to do when it is too high

Five options, roughly in order of how often they are the right one.

• Widen the audience. The most common fix, because a small audience is usually the actual cause rather than the creative.
• Reduce the budget or shorten the run. If the audience genuinely cannot be wider, then the spending has to match the size of the room.
• Set a frequency cap. Available on some objectives. It limits how often one person can be shown the advert in a given period.
• Refresh the creative. Worth doing, but it treats a symptom. A new advert shown to the same exhausted audience helps less than people expect.
• Exclude the people who already converted. They are still in the audience, still being shown the advert, and still costing money.

Words you will hear

• Frequency cap. A limit on how many times one person may be shown the advert within a set period.
• Ad fatigue. The falling response that follows repeated exposure to the same creative.
• Audience saturation. The point at which the platform has shown the advert to everybody your targeting allows.
• Negative feedback. Hides, reports and unfollows, counted by the platform and used when it decides what to show next.
• Effective frequency. The number of exposures a message supposedly needs before it registers. Treat any specific figure with suspicion, because it varies by product, audience and how familiar the business already is.

Frequency is an average, and averages hide their tails. A reported figure of four can mean everybody saw the advert four times, or it can mean most people saw it twice and a small group saw it fifteen times. The second group is the one writing complaints. Read frequency beside engagement rate and the trend in cost per result, and the shape becomes obvious well before anybody starts hiding your adverts.