How CPA model work?
How actually the CPA model works for Google Adwords search campaigns? What are the factors that Google looks into to show my ads to people who are more likely to convert? How an account manager can optimize the campaign settings to help Adwords system in doing this?
Re: How CPA model work?
CPA (Cost per Acquisition), as you would be knowing, is calculated as Total Cost/Total Conversions.
For your question, What are the factors that Google looks into to show my ads to people who are more likely to convert?
Google doesn't decide on its own how to show/rotate the ads. It depends on your Campaign's Ad Rotation setting that you have chosen. Ad Rotation includes below options:
Optimize for clicks: Show ads expected to provide more clicks
Optimize for conversions: Show ads expected to provide more conversions (the one you are looking for)
Rotate evenly: Show ads more evenly for at least 90 days, then optimize
Rotate indefinitely: Show lower performing ads more evenly with higher performing ads, and do not optimize
Based on above options and your selection, Google shows/rotates your ads.
Hope it helps.
Re: How CPA model work?[ Edited ]
July 2015 - last edited July 2015
It sounds like you are asking about Conversion Optimizer which is a a feature that you may be eligible to enable that would allow Google to determine when and to whom to show your ads (based upon your keyword set) and what to bid. You must qualify for this feature by having 15 conversions in the past 30 days in any given campaign that would employ the feature. This is because Google has to have enough historical data to determine when your ads are most and least likely to convert.
Google will use this historical data to determine how to bid for each auction with the goal of generating as many conversions as it can for your budget, at or below the CPA that you have defined.
You can read more about Conversion Optimizer Here: https://support.google.com/adwords/answer/2471188?hl=en
and also here: https://support.google.com/adwords/answer/2390684?hl=en
A similar question was posted in the forum with some additional answers that you might like to read - you can find it here: https://www.en.adwords-community.com/t5/Basics-for-New-Advertisers/conversion-optimizer/td-p/457618
*Note - if you employ this feature, all of your bids will be ignored *except* a -100% mobile bid modifier.
I hope this helps!