We have a particular Adwords campaign for which I'm struggling to monitor its performance - due to the nature of our business, it is very rare for a customer to use the enquiry/contact us forms from the landing pages, instead preferring to pick up the phone. (since the phone number is at the top of every page automatic conversion tracking isn't the best solution).
We make a point of asking every customer where they found our details, but as you can appreciate, tying this to a particular campaign is, at best, difficult.
Can anyone suggest any metrics (either in Analytics, Adwords or GWT) I can use to help me understand the campaign's performance (pages/visit, bounce rates, etc).
Or, more succinctly: a Google Analytics custom report/advanced segment for offline tracking of Adwords conversions.
The only way is to use tracking numbers or tracking phone extensions. There are several companies that provide this.
We have a campaign where we show specific phone numbers depending on the campaign. You can pay more and get it at the ad group or keyword level. When a phone call is made and it lasts longer than 2 minutes a conversion page is loaded that counts as an analytics goal.
I also have it set up so that the are given a cookie and keep getting the same phone number each time they come back.
The more you pay the more accurate your data is. It just depends on how granular you want your conversion data.