Whoa! Don't touch that back button YET!
What? this doesn't 'engage' you?
How about this version and explanation?
Σ(Ci + Di + Ri + Li + Bi + Fi + Ii)
Where
“Visitor Engagement is a function of the number of clicks (Ci), the visit duration (Di), the rate at which the visitor returns to the site over time (Ri), their overall loyalty to the site (Li), their measured awareness of the brand (Bi), their willingness to directly contribute feedback (Fi) and the likelihood that they will engage in specific activities on the site designed to increase awareness and create a lasting impression (Ii).”
"The components of the Visitor Engagement calculation are:
• Click Depth Index: Captures the contribution of page and event views
• Duration Index: Captures the contribution of time spent on site
• Recency Index: Captures the visitor’s “visit velocity”—the rate at which visitors return to the web site over time
• Brand Index: Captures the apparent awareness of the visitor of the brand, site, or product(s)
• Feedback Index: Captures qualitative information including propensity to solicit additional information or supply direct feedback
• Interaction Index: Captures visitor interaction with content or functionality designed to increase level of Attention the visitor is paying to the brand, site, or product(s)
• Loyalty Index: Captures the level of long-term interaction the visitor has with the brand, site, or product(s)"
You can read about that and MUCH more in the whitepaper entitled:Measuring the Immeasurable: Visitor Engagement by Eric T. Peterson and Joseph Carrabis. Engagement in the educational experience is essential! This too is a must read -- and an opportunity to join the conversation about engagement here. And just to whet your appetite, it documents Omniture's response to the subject of measuring engagement (and the author's response to their response):
"The same guys that want you all to believe web analytics is easy has now declared that “Visitor engagement formulas are largely another fad, just like parachute pants and the Hollywood diet. It’s a measure some consultants and vendors can pitch like snake oil.”Read More......
Omniture’s point that Visitor Engagement is a bad idea because it has subjective components fails to understand the work that folks like Jim Novo, Steve Jackson, Theo Papadakis, Joseph Carrabis and others have done; it makes me wonder if the author bothered to read anyone’s work on the subject."