So your ad is sitting on position 1 on Google, and you get a reasonable amount of clicks a day. Your ROI is excellent and you think you have optimized your campaign to it’s full potential… You may also be mistaken.

One of the metrics in the Google Adwords reports that is often overlooked by search engine marketers is impression share. Impression share is basically your campaign’s market share of all the impressions it is eligible for. If you are bidding on the word ‘widget’ you would ideally like your ad to be shown every time a user searches Google for this term. Many people will be surprised to hear that this is not the case, not even if your ad is normally in the top position.

Here’s why: every time a user enters a search queries, Google executes an auction to determine which ads should be shown. As your competitors come and go, and alter their bid prices, your ad does not always win this auction. Sure, on average you might be doing OK but most likely you don’t win every auction.

According to the Google reports, there are two reason why you might not reach your maximum impression share. Firstly, if your daily budget is too low, Google will exclude you from certain auctions in order not to exceed your budget. In the other case, you lose the auction because your ad rank is too low.

Google defines ad rank as the product of Quality Score (QS) and your max CPC so increasing either of these two factors will increase your ad rank. Unfortunately, Google only reports on impression share on a campaign level, so you need to structure your campaigns cleverly to make optimal use of this data. For instance putting all your trademarked keywords in a seperate campaign will help you to determine how often your ads are shown when someone searches for your brand (ideally, this should be 100% of the time).

The easiest way to increase your impression share is to increase your max CPC. Increasing your bid prices doesn’t mean that your effective CPCs will increase, especially not if you’re already occupying the number 1 position. It does definitely increase your risk though, as a determined competitor could send your CPCs soaring. And it definitely will increase your total costs as you will gain more impressions and more clicks. But as long as your are generating profit from your increased traffic, it makes sense to try and grow your impression share.

Obviously obtaining a 100 percent impression share is unlikely to be a viable goal. But looking at this metric will give you a good idea of the size of your potential market and your position in it.