How do you know how much impression share you have with your PPC campaign? Wish there was a way to find out? There is with Google Adwords Competitive Metrics columns.
Search Impression Share - the impressions you’ve received on the Search Network divided by the estimated number of impressions you were eligible to receive. How often your ad is shown depends on your ads' targeting settings, budget, approval statuses, bids, and quality.
Search Exact match impression share (IS) - the impressions you've received divided by the estimated number of impressions you were eligible to receive on the Search Network for search terms that matched your keywords exactly (or were close variants of your keyword). How often your ad is shown depends on your ads' targeting settings, approval statuses, bids, and Quality Scores. This metric can identify potential opportunities to capture more exact match impressions and clicks. It’s updated once a day.
Search Lost impressions share (rank) - the estimated percentage of impressions on the Search Network that your ads didn't receive due to poor Ad Rank. A high Search Lost IS (rank) means there were many times your ad was eligible to show on the Search Network but didn't because its Ad Rank was too low. Search Lost IS (rank) is updated once a day. If you're seeing a high Search Lost IS (rank), try increasing your bid or improving your Quality Score. If you're not seeing a number at all, it could be because you ran out of budget during this date range.
Search Lost impression share (budget) - estimates how often your ad didn't show on the Search Network due to low budget. Search Lost IS (budget) is the estimated percent of times that your ad was eligible to show on the Search Network but didn't because your budget was too low. This estimate is updated once a day. If you want to capture more impressions, try raising your budget
These are some ways you can judge how you stack up against the competition and whether you should increase your budget or capture more impressions with an increase in CPC.