Establish the value of the project and the value of a lead that comes out of it. Valuing the project will come out of your own outlay of resources, more often than not, the man-hours for research and material production. If the campaign is designed to promote a white paper on general industry tips and techniques, you might get a large number of leads, but many may just be looking for the information and not necessarily your product—thus give them a lower individual value on which to calculate the ROI.
You need objects. Use anything related. Call-to-actions across all outlets, social posts, blog posts, The more you have to work with, the more you can see the success and lesser successes (IMO, no effort should ever be termed a “failure”. You gave it a shot. Not trying is the failure). Individualizing items for each outlet is ideal, that way you know specifically what sources drove the most traffic, and which served up the best traffic.
You did all the hard part already! Now take a look at what you’ve done. Like with all analytics, it’s only useful to track the information if you take a look at what it says. Programs which allow you to track and easily manage campaigns as a whole and within their individual objects (like Spectate) help you observe this data at a glance and track it over time.
The more the merrier.
The number of campaigns you have let you really see what works and what doesn’t. ROI is the bread and butter of marketers and the way to illustrate effectiveness on a financial level (which is most relevant over other stats like facebook likes or retweets). So get out there and segment, segment, segment!