Critical reaction aside, the question remains: How is “Agents of S.H.I.E.L.D.” actually performing in the ratings and viewership since its record-breaking premiere episode? While the numbers certainly didn’t remain as high as the premiere, it’s by no means a weak show, and is actually stronger than many folks realize.

WHAT ARE NIELSEN RATINGS?

Before digging too deep into charts and graphs, it’s important to understand what these numbers mean. Nielsen ratings represent a percentage of viewers in a given age group; if a show gets a 2.6 rating for adults 18-49, it means that 2.6 percent of all 18-49 year olds watched that show during its live airing. Relatively simple.

While 2.6 percent might not seem all that impressive at first glance, keep in mind that — as of 2010-11 — Nielsen determined there were 131 million adults in the 18-49 age bracket. So that 2.6 rating in 2010 meant 3.406 million people watched the show during its live airing.

Why is the 18-49 demographic the most important? The short answer is that most ads are tailored to that age group, in large part because they’re the people most likely to spend money. The higher the percentage of 18-49 year olds watching a show, the easier it is for networks to sell ad space and get more revenue out of a series.

That said, live ratings no longer give as complete a picture of the health of a series as they once did — the advent of the DVR and next-day streaming services like Hulu can increase viewer numbers and ratings significantly, though how much it influences a network’s approach to renewing a series remains pretty much unknown.

Another term to be aware of — especially given that the most recent one just ended — is “Sweeps.” These ratings periods involve Nielsen sending out paper television viewing diaries to households across the country, helping provide a basis for program scheduling and advertising decisions for local television stations, cable providers and potential advertisers. Sweeps periods take place in November, February, May and July.

THE STATUS OF “AGENTS OF S.H.I.E.L.D.”

With all of that in mind, the following graphic charts the viewer numbers and ratings of live “Agents of S.H.I.E.L.D.” broadcasts. All charts are for Live+Next Day adjusted ratings, and all viewer numbers are represented in millions. The total is a combination of Eastern/Central and Pacific airings.

 As the chart indicates, “Agents of S.H.I.E.L.D.” began with its series high and slowly declined to its lowest point for episode 7, “The Hub.” It worked its way back up to end November sweeps on the highest rating in the 18-49 demo the show had in three weeks and the second highest viewer numbers overall. While it’s unknown exactly what contributed the the recent bump in ratings and viewers of last week’s episode, there are two major factors that may explain the upwards trend. First, the impending Thanksgiving holiday, where viewers may have begun vacationing early, giving them more free time to tune in. Second, the previous episode’s tie-in to “Thor: The Dark World” likely helped as well.

The timing of the “Thor” tie-in is not a coincidence. While the film’s November launch date was set very far in advance, “Agents of S.H.I.E.L.D.” cleverly used the movie to help drive its November Sweeps numbers. As more people saw the film and caught the related “S.H.I.E.L.D.” episode online or via DVR playback, a number apparently stuck around for the following episode. The gambit seems to have paid off, for now, at least. Time will tell if the series is able to keep its current bump in live viewers.

“AGENTS OF S.H.I.E.L.D.” VERSUS “NCIS”

That’s all well an good, but there are a few comparisons that can give a clearer picture as to how “Agents of S.H.I.E.L.D.” is doing in the marketplace — chief among them is comparing the show with it’s main timeslot competitor, “NCIS.”

Currently in its eleventh season, “NCIS” is a ratings powerhouse for CBS, and it is significant competition for “Agents of S.H.I.E.L.D.” when fighting for casual viewers, in part due to both shows being of a procedural genre nature. Here’s how “Agents of S.H.I.E.L.D.” tracks next to NCIS in both ratings and viewers.

One very significant note about these charts: the 6th episode of “NCIS” season 11 aired without a new “Agents of S.H.I.E.L.D.” episode opposite it; and episode 9 of “Agents of S.H.I.E.L.D.” aired without a new “NCIS.”

While “Agents of S.H.I.E.L.D.” may not be competing with “NCIS” in terms of overall viewers, it’s a little more competitive for ratings in the coveted 18-49 demographic. And though “S.H.I.E.L.D.” does trend lower than “NCIS,” it’s still the only competitive non-reality force for its timeslot as evidenced by these charts, which detail ratings and viewers for all shows that normally air on Tuesdays at 8PM.

 As you can see, “S.H.I.E.L.D.” is quite literally the only show that comes close to competing with “NCIS” both in the 18-49 ratings and in overall viewership. It’s likely that these competitive ratings for its timeslot helped influence ABC to expand “S.H.I.E.L.D.” to a full 22-episode order. That said, there isn’t a whole lot of non-reality-based competition during “S.H.I.E.L.D.’s” timeslot: “Brooklyn Nine-Nine” has some positive buzz and “Dads” continues to get support from Fox, but neither shows any sign of bringing in numbers comparable to “S.H.I.E.L.D.” A similar phenomenon occurs as relates to “The Originals,” the CW’s “Vampire Diaries” spinoff.

It’s also important to note that, other than “NCIS,” all current non-reality series in the Tuesday 8 PM timeslot are brand-new. Out of the four new shows in the Tuesday 8 PM timeslot, “S.H.I.E.L.D.” is clearly way ahead and could even be considered to be the standout new series of the night when just looking at the number comparisons.

“AGENTS OF S.H.I.E.L.D.” VERSUS 2012-2013

It’s very difficult to evaluate “Agents of S.H.I.E.L.D.” against last year’s ABC show in the same timeslot — namely because it was “Dancing With The Stars” in the fall, “The Taste” as a mid-season premiere, followed by “Celebrity Wife Swap,” then “Splash” in the Spring. All four of those shows are reality-based programming. Comparing “Agents of S.H.I.E.L.D.” — a scripted show — to reality television is a bit like comparing apples and oranges, but it does give a slightly better idea as to how “Agents of S.H.I.E.L.D.” is doing. For ease of comparison, the following chart shows “Agents of S.H.I.E.L.D.” in relation to the numbers that were closest to same Tuesday air date in 2012-2013.

Note: The final week of November was the “Dancing With The Stars” finale and it began at 9 PM instead of 8 PM. There was also a 5th week of October in 2013, but no episode of “Agents of S.H.I.E.L.D.” aired that week.

While “Agents of S.H.I.E.L.D.’s” ratings are higher nearly across the board in the 18-49 demo, the viewer numbers overall are definitely not in the same class as “Dancing With The Stars.” However, the higher ratings of “Agents of S.H.I.E.L.D.” is certainly a point in the scripted drama’s favor over last year’s “Dancing With The Stars.”

“AGENTS OF S.H.I.E.L.D.” VERSUS “SLEEPY HOLLOW”

There is one more comparison we have to make with “Agents of S.H.I.E.L.D.,” one with a show lauded by critics as the surprise hit and critical darling of the 2013-2014 season: “Sleepy Hollow.”

Airing on Mondays at 9 PM opposite almost zero competition, “Sleepy Hollow’s” chief competitor is usually 2 half-hour sitcoms on CBS. (Fox, ABC and NBC air reality programming in the fall on Mondays) That said, “Sleepy Hollow” is up against ratings monsters, even if they are reality shows (“The Voice” on NBC and “Dancing With The Stars” on ABC), two half-hour sitcoms on another network and a CW show. (“Beauty and the Beast”) To top it off, “Sleepy Hollow” is also a genre procedural in its first season. Top to bottom, it’s remarkably similar to “Agents of S.H.I.E.L.D.”

Here are the ratings/viewer comparison charts between “Sleepy Hollow” and “Agents of S.H.I.E.L.D.”

For the most part, “S.H.I.E.L.D.” and “Sleepy Hollow” are neck and neck for ratings and viewership with a few outliers. Critical reaction is certainly on thing — “S.H.I.E.L.D.” is cited for not living up to expectations, while “Sleepy Hollow” is praised for having exceeded them — the shows both are following similar trajectories in terms of ratings and viewers.

WHAT DOES THIS MEAN FOR “AGENTS OF S.H.I.E.L.D.”?

Despite critics’ evaluations, “Agents of S.H.I.E.L.D.” is performing very well, certainly well enough to understand why ABC chose to commit to a full season order. Any show that can even come close to the constant 3.0 ratings of “NCIS” on Tuesdays is a decently sound investment for ABC. At this point, the only thing that would probably prevent the series’ renewal is if the numbers start to trend downward beyond normal show attrition.

That said, if “Sleepy Hollow” is bringing in the ratings it does on a night largely devoid of scripted television and continues its climb as critics’ it girl of the 2013-2014 season, imagine what “Agents of S.H.I.E.L.D.’s” ratings would be like if it were getting similar acclaim.

Bottom line is, the numbers are very strong for the current market. The fact that the only scripted show “Agents of S.H.I.E.L.D.” can’t beat in its timeslot is “NCIS” makes it a much more likely bet for ABC renewal — especially given the .2 gain each week in the ratings since November 12.

All data sourced from TV by the Numbers.