The vast majority of delayed viewing that Nielsen measures happens within the first three days after a show airs.

The unwatched shows sitting on America's DVRs generally don't stay there for more than a few days.

Even a relative outlier like NBC's This Is Us — the biggest gainer in the back end of Nielsen's delayed-viewing measurement — picks up a relatively scant percentage of its total audience as the days after an episode airs pile up.

The Hollywood Reporter's analysis of live-plus-7 viewing for the 2018-19 season shows the vast majority of viewing as measured by Nielsen happens within the first three days of a show's on-air debut — more than 90 percent of it on average, in fact. Even in cases where shows get more than half of their audiences after they first air — two dozen broadcast series are at least doubling their 18-49 ratings after a week — the bulk of that happens in the first three days.

Nielsen publicly releases three sets of ratings for shows: live-plus-same-day, for viewing the night a series airs; live-plus-3, for viewing within three days of air; and live-plus-7, for viewing within a week. For the 2018-19 season so far, only one show, The CW's All American, gets as much as 20 percent of its seven-day total among adults 18-49 after three days (it grows from a 0.3 rating after three days to 0.4 after seven).

On average, network entertainment series (not sports or news programs) get just 9 percent of their seven-day 18-49 ratings after day three, and only 7 percent of their total viewers between days three and seven. Those figures don't include streaming, which isn't measured in the same way.

In the first three days after air, by comparison, shows pick up about 27 percent of their eventual seven-day totals in adults 18-49 and 23 percent of their total viewers.

(Caveat: The numbers that really matter to advertisers are the C3 and C7 ratings, which measure how many people actually see the commercials that help pay for programming and are rarely disclosed publicly. They tend to be lower than the live-plus-3 and live-plus-7 ratings.)

It's not just a broadcast trend, either. While season-long delayed viewing averages are hard to come by for cable series, the top 50 entertainment shows on cable the week of Feb. 11 were right in line with the network averages: 9 percent of their seven-day 18-49 ratings and 6 percent of their total audiences watched after day three.

In terms of raw numbers, the average entertainment show only adds 0.1 to its 18-49 rating and 484,000 viewers after day three.

This Is Us posts the biggest gains between three and seven days, growing by 0.6 points in the 18-49 demo and 1.64 million viewers. Still, since it's a high-rated show to begin with, those numbers represent only 15 percent of its 18-49 average and 12 percent of its total audience.

The other biggest day-three-to-day-seven gainers — CBS' The Big Bang Theory, NBC's Manifest and New Amsterdam, ABC's The Good Doctor — are also solidly rated at all three stages, and their gains in the latter part of Nielsen's measurements aren't much higher than those of This Is Us.

Here are the top 10 shows (including ties) in gains after three days in adults 18-49 and total viewers.

Adults 18-49

Show Network Live + same-day rating Live +3 rating Live +7 rating % of L+7 rating after day 3 This Is Us NBC 2.1 3.4 4.0 15% The Big Bang Theory CBS 2.3 3.4 3.8 11% Manifest NBC 1.3 2.4 2.8 14% The Good Doctor ABC 1.1 2.1 2.5 16% New Amsterdam NBC 1.2 2.1 2.5 16% Modern Family ABC 1.3 2.1 2.5 16% The Masked Singer Fox 2.4 3.4 3.7 8% 911 Fox 1.4 2.3 2.6 12% Chicago PD NBC 1.1 1.8 2.1 14% Criminal Minds CBS 0.8 1.4 1.7 18% The Rookie ABC 0.8 1.3 1.6 19% Bull CBS 0.8 1.3 1.6 19% Grey's Anatomy ABC 1.7 2.7 3.0 10% The Passage Fox 1.0 1.6 1.9 16%

Total Viewers (in Millions)

Show Network Live + same-day viewers Live +3 viewers Live +7 viewers % of L+7 viewers after day 3 This Is Us NBC 8,618 12,514 14,153 12% Manifest NBC 6,562 11,225 12,757 12% New Amsterdam NBC 6,363 10,260 11,702 12% The Good Doctor ABC 6,655 11,217 12,650 11% The Big Bang Theory CBS 12,962 16,478 17,637 7% Bull CBS 6,743 10,408 11,556 10% 911 Fox 5,853 9,062 10,197 11% NCIS CBS 12,227 15,001 16,077 7% FBI CBS 9,175 11,695 12,740 8% The Rookie ABC 4,229 7,415 8,394 12%

Source: Nielsen

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