You might often find that there are no ads on a page, even when an advertiser is bidding on the search terms that generated those results. In order to be consistent with our philosophy of showing the right ad to the right user at the right time, we'd rather show no ads on a page than show low-quality ads. That's why every ad needs to meet the Ad Rank thresholds in order to show. In some cases, low-quality ads may hardly show at all (even if you keep raising your bid), because those ads don't exceed the minimum quality standards necessary to show. You can find out why your ad may not be showing for a given query by using keyword diagnosis.

Remember that competition is only one of the variables that determines your actual CPC. The price you pay for a click is also determined by the quality of your ads and the context of the person’s search terms, among other factors. If your ads and landing page are low quality, you may find that your actual CPC is close to your maximum CPC, even though there is low competition for the search terms that triggered your ad. When your ads do show, keep in mind that you'll never be charged more than your maximum CPC for a click (unless you use automated bidding), no matter how low your ad quality.

To show more relevant information to users, we include the expected impact from your extensions and other ad formats when calculating your Ad Rank, which also takes into account your bid, the quality of your ad and landing page, Ad Rank thresholds, and the context of the person’s search.

We consider several factors when determining whether to show an ad extension on Google, including the position of your ad on the Google search results page (for example, some extensions only show in ads above search results). We also require a minimum Ad Rank (factoring in your extensions) before showing extensions. Keep in mind that raising your bid, improving your ad quality, or both, can improve your Ad Rank. And improving your Ad Rank increases the chances of your ad extensions showing with your ads as well as the likelihood that your ad will get more clicks.

Expected clickthrough rate (CTR) is one of the quality components of Ad Rank. When determining expected CTR, we look at the past performance of your ads, but when doing so, we exclude the past effects of ad position. As you might have seen, ads in high positions typically earn better CTR than those in low positions, because ads in high positions are more prominent and visible to users. Therefore, to calculate the most accurate expected CTR, it's important that the influence of ad position (as well as other factors that affect prominence and visibility, such as extensions and other ad formats) on expected CTR is taken into account and removed from the determination of expected CTR.

Ad quality is calculated based on auction-time estimates of your expected clickthrough rate, ad relevance, and landing page experience. Your bid is not considered when determining the quality of your ads.

For ads above Google search results, we use the same Ad Rank formula, based on your bid, the quality of your ad and landing page, the context of the person’s search, and the expected impact of extensions and other ad formats. However, only ads that exceed the higher Ad Rank thresholds are eligible to appear above Google search results. This ensures that quality and relevance play an even more important role in determining the ads that show above search results. It can help to make sure that people see higher quality ads higher on the search results page, and that the Actual CPC paid by advertisers reflects the prominence and value of the ad’s location on the page.

Some advertisers using Google Ads conversion tracking mistakenly believe that they should set an easy conversion event on their landing pages to artificially boost their conversion rates. In reality, this will not have any effect on the quality components of your Ad Rank. Feel free to use conversion tracking responsibly, and don't worry about its impact on your ad quality.

When your ads are paused or not showing due to budget or low bids, the quality of your ads is not affected.

In order to optimize your account, we encourage you to run targeted tests on your bids, creatives, and keywords.  These small tests are a useful way to measure the impact of changes before applying them to the rest of your account. You should carefully track the performance of your experiments. If you notice that they don't perform well after a few days, you can revise your experiment or remove those changes.  The short-term impact on the quality of your ads will eventually be outweighed by the previous and future performance for that keyword.

The history of keywords, ad texts, and landing page is preserved when you restructure your account. This is also generally true when moving keywords and ad texts across accounts or into new ones (as the experience from a user's point of view remains the same). Experiment with improved account structures. You can always go back if they're not successful.

The 1-10 Quality Score shown in your account is an aggregated estimate of your overall performance in ad auctions; therefore, it can’t be used at auction time to determine Ad Rank. Real-time, auction-specific quality calculations of expected clickthrough rate, ad relevance, and landing page experience, among other factors, are used to calculate Ad Rank at auction time. These factors, which are based on things known only at the time of the auction, can heavily influence the quality of the user’s experience.