To analyze the performance of each shortener I collected:
Unique Clicks: How many unique visitor Link Clicks were generated. This was the most important information for me, as performance of my websites (and most websites which use paid link shorteners) base on unique visitors. I used Unique Clicks (visitors) to calculate eCPM.
Revenue: How much money I earned with each shortener during the test.
And additional data which could be useful to compare shorteners’ performance:
Link Clicks: How many times my landing-page was clicked.
Counted Views (by shortener): How many views (of the intermediate ad page) were counted by a shortener.
Counted Visitors (by shortener): How many unique visitors were counted.
The data comes from:
Link Clicks and Unique Clicks I tracked on my landing-page with Google Analytics.
Revenue, Counted Views and Counted Visitors is shown in Dashboard of each shortener.