Ad Rank

Ad Rank is the calculation Google Ads runs on every advert entering every auction. It decides two separate things: whether the advert is allowed to appear at all, and where it sits among the ones that do. The figure is worked out fresh for each individual search and never stored against your account, which explains most of what advertisers find puzzling about their own position.

In short

• Recalculated for every advert on every single search.
• Your bid is one of six published inputs, and often not the decisive one.
• It is applied twice: once to decide entry, once to decide order.
• Google does not report it, so you read it through position and impression share.

The six inputs

Google publishes this list, which is more openness than the auction gets elsewhere.

• Your bid. The most you are willing to pay for a click. A ceiling, not a price.
• The quality of the advert and the landing page. Assessed at the moment of the search, not pulled from a stored number. Quality Score reports these same signals back to you afterwards, which is a different job from feeding them in.
• The Ad Rank thresholds. The minimum standard the advert has to clear.
• The competitiveness of the auction. Who else showed up for this search.
• The context of the search. Location, device, time of day, the exact words typed, and what else is appearing on the page.
• The expected impact of assets and formats. Sitelinks, callouts and the rest, which is where ad assets do more than fill space.

Four of those six are outside your hands on any given search. That proportion is the honest answer to why position moves without anybody touching the account.

Once for entry, once for order

The calculation happens twice, and the two runs answer different questions.

The first is a yes or no. Does this advert clear its threshold. An advert that fails is not placed lower down, it is left out, and no bid rescues it. Adverts in an account that stopped serving without warning have usually failed here, not run out of budget.

The second run sorts everything that survived the first, and produces the order on the page. Only at this point does the bid do much work, and it does it alongside the other five inputs rather than ahead of them.

Splitting it this way is what allows two adverts with identical bids to end up in different places, and one advert with a smaller bid to end up above a larger one. Neither outcome is a glitch. Both are the system doing what it was built to do, which is to avoid selling the top of the page to whoever is least careful about what they put there.

Why an empty auction still has a price

This part surprises people in specialised trades, and it is worth understanding before assuming that a quiet market means cheap traffic.

When no competitor clears their threshold, there is no rival bid to price your click against. You are not charged nothing, and you are not charged one unit above zero. You pay the reserve price, which is derived from your own Ad Rank threshold, and your threshold is set partly by the quality of your advert.

The practical consequence reverses the usual assumption. A weak advert alone in its auction can pay more per click than a strong advert fighting three rivals, because the weak advert carries a higher threshold and there is nobody there to undercut it. Advertisers who conclude that competition is the whole story behind their pay per click costs are working from a model that does not include this.

Words you will hear

• Auction. The instant a search happens and eligible adverts compete.
• Threshold. The minimum Ad Rank required, varying by quality, by position and by the nature of the search.
• Reserve price. What you pay when there is no competitor below you to price against.
• Eligibility. Whether the advert may enter at all, decided before order is.
• Ad Strength. A measure of how varied your headlines and descriptions are. Useful, and not an auction input.
• Position. Where you appeared. An outcome of Ad Rank rather than something bought directly.

Reading it without being able to see it

Since the number is invisible, everything you learn about it is inferred, and two reports carry most of that inference.

Lost impression share to rank is the closest thing to a direct reading. It is the share of auctions you entered and did not win, which is Ad Rank falling short, and the impression share columns separate it from the share you lost by running out of budget. The two have nothing in common and get treated as the same problem constantly.

Position, averaged over a week, is the second. It is noisy over a day for the reasons above, and reasonably honest over a longer window.

What neither will tell you is which of the six inputs moved. That has to come from the change history, which records what you altered, and from the quality diagnostics, which describe the state of your relevance and your landing page. Between those two you can usually account for a shift. Without them you are left guessing at a number nobody outside Google can see.