Engagement is a new advertising metric that, oddly enough, no one can quite agree as to what it means, does, or represents.
In theory, engagement is supposed to quantify as accurately as possible a person's interaction with an advertisement, statistically encompassing word of mouth, consumer generated media and, well, any way a person perceives or relates the experience of viewing a successful advertisement. How that data is actually collected is up to market research firms and is beyond the reach of this writeup. Suffice it to say that it involves asking a very carefully crafted set of questions to a statistically significant cross-section of the populations without wasting too much of their time. It's not as easy as it sounds, and it sounds impossible.
There are other people who take this metric to another place entirely; this is where it gets interesting.
The way television works is, advertising spots are sold twice a year, and the cost of commercial time is based on who's watching what and when. The thing is, all those statistics tell you is how many people are watching a program. They don't tell you how closely they're paying attention.
Believe it or not, this is a big deal - people who are more engaged in a piece of programming are more likely to stick around and watch the commericals contained therein instead of getting up to make a sandwich, and if they do make a sandwich, they'll be damned sure to be back in their chairs before the next segment starts. Whereas before, commercial space at the starts and ends of blocks of commercials was priced higher than the spots in the middle, commercial time during programs that are more engaging should really sell based on a different pattern - the most likely commercial to be seen is the one immediately prior to the next segment, not the block following the last one.
All well and good. The only sticky point is, how do you describe how engaging a program is?
There are a couple of ways, but this is the standard method: come up with content-based survey questions about pieces of programming and ask these questions to a portion of the population who are demographically known by age, race, education level, income and by any other metric you can think of. You can then tabulate what percentage of the viewship was actively engaged in the programming and, by comparing ad viewship during programs that have a high level of viewer engagement to recall for commercials aired during those programs, you can nudge your ad rates based on how many people are are actively involved in the show and therefore with the commercials. The downside of this is that it requires questions for every show that airs on television on any given night, and getting that information is tricky.
The point of all this is, of course, money - it's hoped that the engagement metric will eventually replace ratings from Nielsen and the like by telling a network more precicsely what their adspace is worth.