You can't figure out "normal" on a timeslot-by-timeslot basis, because maybe one timeslot is "heavy" the whole season and maybe another is "light" the whole season. We have to do a much bigger picture.
Here's how the whole week lines up. Keep in mind both of these numbers are a little "massaged" by adjustments found in previous posts:
So the average broadcast share of the total viewing audience is 29%. That doesn't vary too wildly across the entirety of the night (though 10:00 doesn't really "count" in making that claim, since we got to that point by adding the 3.54 constant determined from the other two hours).
It does vary from day-to-day, week-to-week, as it should. But there's one gulf that's too big to just write off; as usual, it's the gulf between the weekend and the weeknights.
So the way that I want to look at this is that "normal" competition is equal to 31% of the overall PUT if it's Sunday through Thursday and 24% of the overall PUT if it's Friday or Saturday.
Update (8/9/2011): Due to an adjustment in how much sports "count" in competition, these numbers have each been reduced a hundredth. Now it's 30% during the week and 23% during the week.
But it's worth asking: is that fair to the weeknights to be held to a much higher "standard" of competition? Are the weekend evenings getting a free pass by having their "normal" be much lower percentage-wise? Should it just be 29% for everyone?
I think it is fair. As we explored in some of the early posts about viewing levels, broadcast is not entirely just weaker because of viewing level declines. There's also less of a "good faith" effort made on these nights; in other words, the stuff scheduled on Friday/Saturday isn't big hit kind of stuff anyway, and it wouldn't be on the big nights. These percentages assume something about the networks' "faith," and 31% is about what happens on average when the networks are operating in good faith. 24% is what happens when they're not trying quite as hard. I tend to think it's OK to penalize a show for having light competition when the networks are trying and failing. When the networks aren't even trying, I'm not sure it's fair to hold this stat to the same standard as if they were trying. I think to demand that Friday/Saturday get up to 29% of the PUT (which rarely happens) would take away a big chunk of the "equalization" that the viewing level adjustments make.
Now, we could apply that "bad faith" adjustment to other nitpicked segments of the year (like the second half of December), but to avoid overcomplication, we'll just stick with Friday and Saturday nights for now.
The Formula So Far
Here's what we had at the end of the first of the "big three" adjustments:
PUT-Adjusted True Strength (called PUT-TS below) = A18-49 rating * Early Fall Hype * 33.75 / (PUT * Old Methodology Adjustment)
Early Fall Hype = 0.948 (if in the first six weeks of the season)
Old Methodology Adjustment = 1.270 - (0.046 * hour) (if date is 3/28/2011 or later)
The A18-49 divided by PUT part is explained here.
(The 33.75 constant is an estimated average Old Methodology PUT. It creates a ratio with the actual PUT to create a number relatively close to an actual rating. This number was 33.805 in the previous incarnation but when I calculated it above (and I think that one's more accurate) it was 33.75, so I'll go with that.)
Now, let's throw in what we've come up with competition.
Competition-Adjusted True Strength = PUT-TS * ( 1 + (Competition Adjustment * (bcPUT - Expected bcPUT)))
Competition Adjustment = 0.0375
bcPUT = Sum of known broadcast PUT-TS in the timeslot (plus an additional 3.54 in the 10:00 hour)
Expected bcPUT = 0.31 * PUT (if Sunday to Thursday) OR 0.24 * PUT (if Friday or Saturday)
Here's the whole thing:
Competition-Adjusted True Strength = A18-49 rating * Early Fall Hype * 33.75 * ( 1 + (Competition Adjustment * (bcPUT - Expected bcPUT))) / (PUT * Old Methodology Adjustment)
Next time, we use our brand new Competition-Adjusted True Strength for the first time to look at how sports have too much influence on competition levels.