Impression

An impression is one appearance of your listing, post or advert. It is counted when the content is served or displayed, whether or not anybody clicked, read or even noticed it. Almost every marketing report begins with this number, and it is the one most likely to be misread.

In short

• It counts appearances, not people and not attention.
• Repeats count, so one person can produce many.
• The rules for counting one differ on every platform.
• It is context for the numbers underneath it, not a result.

What actually gets counted

The rule is simpler than most people expect. Your content entered a place where it could have been seen, so one is added to the total.

That is the whole definition on most platforms, and it explains almost every argument about the number. A search listing that appeared at the bottom of the second page counts. A post that entered the screen while somebody was scrolling past at speed counts. An advert loaded below the visible area of a page may or may not count, depending on whether that platform applies a viewability rule before adding it.

None of this makes the figure dishonest. It makes it a measure of distribution rather than a measure of interest, and those are different things that get reported in the same row.

Impressions, reach and clicks

Three numbers usually appear together and each answers a separate question.

• Impressions. How many times it appeared. Repeats included.
• Reach. How many separate people it appeared to. Repeats excluded.
• Clicks. How many times somebody acted on it.

The relationship between the first two is the useful part. Divide impressions by reach and you get frequency, which tells you how often the average person saw the thing. Two campaigns with identical impressions can be a broad announcement and a small group being shown the same advert eight times, and only the second one is at risk of annoying people.

Clicks divided by impressions gives click-through rate, which is the measure of whether the appearance was any good.

Where the counting rules differ

Every platform counts impressions its own way, and the differences are large enough that adding totals from two of them together produces a number describing nothing.

• Search. An appearance in the results for a query. Google Search Console counts an impression even when your listing sat below the point most people scroll to.
• Social. An appearance in a feed. The share of the post that had to enter the screen before it counts varies by platform and changes over time.
• Display and video advertising. Often subject to a viewability standard, where a proportion of the creative must be on screen for a minimum period before the impression is counted as viewable.

The practical rule that follows is to compare a platform against itself and never against another one. A month on month movement inside one account is meaningful. A total assembled from three platforms is arithmetic without a subject.

When the number is useful

Impressions earn their place in three situations.

They show whether you are being distributed at all. A page with no impressions is not being shown, which is a different problem from a page being shown and ignored, and only this number separates the two.

They show the size of the opportunity. High impressions with low clicks means people are seeing you and choosing something else, which points at the listing, the offer or the position. Low impressions with a healthy click-through rate means the message works and too few people are getting it.

They show when something changed. A sudden movement with no change in spending or activity is usually a platform doing something, and noticing it early is worth more than explaining it later.

Outside those three, the number mostly flatters. Impressions rise when budgets rise, when audiences widen and when a platform decides to distribute more. None of that is an achievement, and a report that leads with impressions is often a report avoiding the figures underneath.

Why the number moves on its own

An impression total changes for reasons that have nothing to do with anything you did, and knowing the common ones saves a great deal of misplaced credit and blame.

• Budget. On paid campaigns the two move together almost mechanically. More money buys more appearances.
• Audience size. Widening a target audience or loosening a keyword produces more impressions immediately, before anything about the message has improved.
• Competition. Fewer advertisers bidding in your market means your adverts appear more often at the same spend, and a busy season reverses it.
• Platform changes. A layout change in the search results, a new feature taking space above the listings, or an adjustment to how a feed distributes posts moves everybody’s totals at once.
• Seasonality. More people searching means more chances to appear, which is why a December total tells you almost nothing about December unless it is read against last December.

Because five of those six are outside your control, an impression figure taken alone is closer to a weather report than to a scoreboard. The question to ask of any movement is which of these changed, and only when none of them did is the change about your work.

Words you will hear

• Served impression. Counted at the moment the content was delivered.
• Viewable impression. Counted only once enough of it was on screen for long enough.
• CPM. The cost of a thousand impressions, used where you buy appearances instead of clicks.
• Frequency. Impressions divided by reach.
• Share of voice. How much of the available appearance was yours, which for search advertising is impression share.

Impressions are the widest number in any report and the easiest to grow without achieving anything. Put them next to clicks, inquiries or orders every time, and treat a rise on its own as a question about what changed rather than as news.