This article explains when to use click share, how click share works, and how to increase your click share. 

Click share is the clicks you've received on the Search Network divided by the estimated maximum number of clicks that you could have received.

When to use

To understand the value of click share, you can compare it to the results you see for impression share. While impression share tells you about your share of eligible impressions, click share tells you the share of clicks you could get for the eligible impressions. But, when your impression share may be high, even 100%, you may still only receive a small number of clicks. You can use click share to understand how close you are to receiving the maximum number of possible clicks.

How it works

Similar to impression share, Google Ads analyzes the ad auctions over the course of the day and includes all auctions that your ad showed in or your ad was competitive to show in.

To estimate click share, Google Ads compares the number of clicks you actually received with the maximum number of clicks you could have received. The maximum number of clicks you could receive depends on the prominence of your ads and the number of ads you show for a search query. These two factors are influenced by several other factors including your bid and the overall quality and relevance of your ads.

Keep in mind

• Click share includes all auctions where your ad showed or where your ad was competitive in the auction. For example, it could include auctions where your ad could show at twice its current bid, but could exclude auctions where your ad is estimated to need a 1,000% bid increase in order to appear.
• Since click share is based on an estimate of when your ad was competitive in the auction, small fluctuations over time don’t necessarily mean you need to make a change. Changes to your bids, the overall quality and relevance of your ads, or Google's ad systems may change the set of auctions in which the system estimates you were competitive.
• Your eligible clicks can grow. Though you may see your clicks increasing, the total number of auctions where your ad is competitive (or users looking for your products) can also increase throughout the year. If total clicks available is growing faster than the clicks you receive, you might be losing click share to your competitors. 

Data notes

• You can view click share data only for Shopping campaigns. Click share information is available at the product group, ad group, and campaign level.
• All click share metrics are updated once per day at approximately 2pm Pacific Time [GMT-8]. As a result, the click share data you see won’t reflect the current day, and it may not include the previous day's click share as well (if you are running your report before 1pm). For example, click share data for Monday won’t be available until after 1pm on Tuesday.
• Click share for Shopping campaigns is available from September 9, 2015.

How to increase your click share

• Remember you need to get impressions before you can get clicks. Everything you can do to increase impression share and absolute top impression share is also useful for increasing click share. Learn about how to increase impression share.
• Even if you have a high impression share, your click share may still be lower. Increasing your bid and the quality and relevance of your ads can help your ads get higher positions and more clicks.
• Remember that multiple Shopping ads from the same advertiser can show at the same time. When you have multiple ads showing at the same time, you increase your chance for having any of your ads clicked. So, you can increase overall click share by having more than one of your products show. Each additional impression raises your chance for a click.

* Nguồn: Google