In a sense, there are two kinds of fans of NBC’s “Parks and Recreation.”

The ones who also like CBS’ “The Big Bang Theory” but can’t understand why that show crushes “Parks” so badly in the ratings.

The ones who don’t like CBS’ “The Big Bang Theory” and can’t understand why that show crushes “Parks” so badly in the ratings.

I’m a member of the first group, but that’s not really important. The question isn’t why there’s a ratings gap between the two shows, but why is it so freakin’ big?

How big?

Taking last week’s numbers as an example, “Big Bang” drew a 5.1 rating in the 18-49 demo and 17.6 million viewers overall, while its Thursday 8 p.m. counterpart “Parks” managed a 1.2 and 3.2 million.

If you think it’s a case of a bunch of viewers DVR-ing “Parks,” while watching “Big Bang,” think again. When the delayed viewing numbers come in, the gap between the two shows widens.

In Live+3 last week, “Big Bang” improved to a 7.2 rating in the demo, a gain of 41% (2.1 ratings points). By comparison, “Parks” improved to a 1.6, a 33% gain (0.4 ratings points) on a much smaller base number to begin with.

Sure, CBS brings a bigger foundation of viewers to the table, while NBC is far removed from the days of “Must-See” Thursdays. You could also argue that the multi-cam, set-up/joke style of “Big Bang” is easier to settle into than the more nuanced (I almost wrote “cerebral,” but that diminishes “Bang” unfairly) single-cam stylings of “Parks.”

And there’s no doubt that “Big Bang” has benefited from how its syndication saturation widened its tent of viewers, while “Parks” is just getting started down that road.

On the other hand, it’s not as if “Parks” has so little going for it. The cast is nothing if not marketable. Amy Poehler is the former “Saturday Night Live” star and brilliant comic actress who also happens to be part of the most sought-after awards-hosting duo in the business. Aziz Ansari has a hot standup career. Chris Pratt has evolved from lovable oaf to action star. Retta is one of the most adept users of social media around. Rob Lowe is … Rob Lowe. That’s before you even get to Adam Scott, Rashida Jones, Aubrey Plaza, not to mention great guest casting.

I mean, is any character more tailored for a hunk of CBS’ audience than Nick Offerman’s Ron “F’in” Swanson?

Though there are some fans of one show who might find the comparison to the other demeaning, the sensibilities and humor of the two shows are not all that different. Their styles might differ, but both are clever, exceedingly warm and the opposite of mean-spirited. Even the ostensible targets of derision, such as Jerry (Jim O’Heir) are treated with affection. Both series value their characters and serialize their arcs.

“Big Bang” might be multicam, but it’s probably the smartest multicam sitcom around. Its viewership should embrace “Parks” more than the numbers indicate. It’s not as if “Parks” is rocket science to follow or to find the jokes in — or for that matter, the beauty.

Weigh it all together, and as much you expect some gap, the size of the gap remains hard to fathom.

“CBS has been more successful with viewers whereas NBC has been struggling to get an audience,” Horizon Media senior research veep Brad Adgate told Variety. “I think that’s a factor. Plus ‘Big Bang’ is on a top-rated cable network on primetime every night, unlike ‘Parks.’ ‘Big Bang’ is a show that viewers will seek out. I think ‘Parks’ needs help for viewers to find it. It is mysterious, though, I agree. It’s kind of strange, but ‘Big Bang’ is so popular it just kind of builds. “

The chasm has implications beyond the fate of “Parks” itself for NBC, which is struggling more than ever with its Thursday lineup in its first season since “30 Rock” and “The Office” bid farewell. Newcomers “Welcome to the Family,” “Sean Saves the World” and “The Michael J. Fox Show” are in dire straits to various degrees. A new season of “Community” remains at NBC’s disposal, but that’s another example of a cult favorite, not a ratings solution.

All the people at “Parks” can do is continue trying to make the best show they can make.

“As far as ratings go, I don’t really think about it,” “Parks and Recreation” showrunner Michael Schur told Variety. “Or, I try not to. All I know for sure is that the number that comes out at 8 a.m. every day is a wildly inaccurate picture of the number of people who watch any show, and everyone needs to stop reporting it as such. As far as one show versus another, who knows? It’s not one thing — like network or timeslot or something — it’s a combo platter, and one I do not fully understand.

“I (do) think ‘Big Bang’ is an extremely well-made show, and it is not at all a surprise to me that it is a smash hit.”

At the end of the day, maybe the NBC marketing solution should be this: “If you like ‘The Big Bang Theory,’ then you should give ‘Parks and Recreation’ a try.”