True Index

True is a metric first introduced in summer 2011 that takes the Live + Same Day adults 18-49 rating (the publicly available number that most closely correlates with advertising rates) and adjusts it for the three big external factors that affect TV ratings: overall viewing levels, timeslot competition and lead-in rating. The output is a number more reflective than the raw 18-49 rating of the show's "true strength." While True does not improve the correlation with ad dollars (since advertisers pay for actual eyeballs), it provides a better look at opportunity cost dynamics by helping to predict how each show would do in a more normalized situation.

The Formula

The second version of True, in which most of the formula was overhauled, came out in summer 2012. Here are the posts laying out that version of the formula:

Viewing | Lead-ins | Competition pt1 | Competition pt2 | Wrap-Up

And here are the details on the relatively limited True tweaking during summer 2013: The 2013 True Tweaks.

Day-to-Day Implementation

The final True calculations for every regular broadcast program on TV can be seen in the SpotVault. Most Vault updates for the previous week come on Wednesday (when I get the half-hour breakdowns that allow me to make the most accurate True calculations).

On each daily ratings post, I post the preliminary True calculations for each program. These are less accurate because they're based only on full program ratings, but on average they're within about 5% of where the final will end up.

Each Wednesday, I look at the "True Top 25" programs from the past week, a way to compare the biggest programs on TV while accounting for their respective timeslot situations.

And several times over the course of each season, True unites all broadcast primetime programs by network for the ultimate look at relative strength, the True Power Rankings. There's also a weekly, analysis-free edition introduced in 2012.