Google Adwords Metrics

The first position bid estimate is the likely cost-per-click (CPC) bid you will need to set for your ad to appear in the first ad position on the search engine results page (SERP). It is an estimate based off of each keyword’s quality score and isn’t a guarantee. If you bid below the estimate, you ad may still appear in the first ad position but is unlikely to do so. If you bid at or above the estimate, you are more likely to appear in the first ad position.