In January 2012, when FX president John Landgraf took to the stage at the Television Critics Association press tour to take aim at the Nielsen ratings, he was a lone voice of caution. Explaining that just a third of FX viewers were watching the network’s shows either live or recorded in the first day that episodes aired, he suggested that television had not just a business problem, but a cultural one.

The cast of NBC’s “Parks and Recreation.” Thirty-seven percent of the show’s viewership is not captured by conventional ratings systems. (Chris Haston/NBC)

“I think we all understand that the nature of television viewing is undergoing a radical transformation,” Landgraf said, “and I think we would all agree that there is a value in finding a way to let readers know the true magnitude of audiences for TV series rather than only seeing numbers which reflect a fraction of that viewing.”

Two and a half years later, other executives are on board — and the rest of us should be, too.

CBS president and chief executive officer Les Moonves, whose network fares best under the conventional ratings system, acknowledged last summer that he would like to see changes to the ratings system because “Everything is not quite being counted yet, although Nielsen is trying to get there.” And this week, a striking presentation from Alan Wurtzel, NBC’s president of research and media development, at the most recent TCA press tour in Los Angeles suggested just how far we are from knowing the real size of television viewing audiences.

NBC uses a metric it calls the “Total Audience Measure Index” to tote up Nielsen ratings, viewings through DVRs and video on demand, and digital viewing to try to get a more complete portrait of viewership, Wurtzel explains. The TAMI suggests that a huge amount of television watching, especially by younger viewers, simply is not captured by Nielsen ratings.

Seventeen percent of viewers between ages 18 and 24 who watch “Parenthood,” for example, do it digitally. A whopping 45 percent of viewers in that demographic who tune in for “Parks and Recreation” do so online. Across all age groups for “Parks and Recreation,” “37 percent of that viewing of that show is being done on the platforms that nobody ever sees,” Wurtzel explained.

From a business perspective, it is an enormous problem for Wurtzel, Moonves and Landgraf that while, as Wurtzel put it, “They’re all equivalent. They’re all our viewers. They’re all engaged in that show,” they cannot make the same money off of all of those viewers.

But from a cultural standpoint, there is something fascinating about our inability to precisely map the landscape of television.

With books and movies, it is reasonable to assume a connection between what people spend money on and what they actually consume. Sure, maybe you have to do a little math with box office receipts and average ticket prices to figure out how just how many Americans want to go see giant robots fight each other on any given weekend.

But for television, many of us pay for a package of networks, rather than for individual shows or episodes. The purchase or streaming of episodes is not built into the structure for tracking viewership. And because of the way the Nielsen ratings system is set up, even those of us who might be willing to share our watching data to help bolster the case for renewing our favorite shows are locked out of the system that collects that information.

Of course it is nice to think that if we just had better data, the television we love best would never be in danger of cancellation again (whether it might outlive its charm is a much less frequent subject of discussion). But there is another reason to wish for some sort of equivalent of NBC’s TAMI, as well as for ratings data from newer players in the television business such as Amazon and Netflix.

Knowing whether something is a phenomenon, or at least a cult hit with deep and abiding roots, is not just a matter of dollars, cents and the imitations that are going to be flooding the market in a business cycle or two. It is part of understanding who we are.

Just as the runaway success of “Fifty Shades of Grey” made visible the sexual yearnings of millions of American women, it might be useful to verify whether shows such as “NCIS” and “The Big Bang Theory” are as dominant as they seem. For those of us who love shows such as “Orange Is the New Black,” it would be useful to know whether Netflix’s prison drama is actually reaching a mass audience or whether it’s just a cult hit among those of us who were inclined toward the subject material in the first place.

changing the minds of a mass audience or just acting as continuing education for those of us who were inclined toward the subject material in the first place.

Of course, for a show to make an impact, sometimes it only needs the right viewer: By now, we all know the story of how sitcom “Will and Grace” helped turn around Vice President Joseph Biden’s thinking on marriage equality. But for the rest of us, there is something powerful about realizing that you are not alone in the things you love. Sometimes that means finding a small but passionate community. Sometimes it means suddenly finding yourself in the mainstream.

Wurtzel opened his presentation by showing the audience a slide of a 1950s family gathered around their television, joking that this was “viewing the way God intended.” We may have parted ways to watch television on our tablets and smartphones. But increasingly, the Nielsen ratings system cannot even tell us if we are united in our private enthusiasms, sharing the same stories in the dark.

Alyssa Rosenberg blogs about pop culture for The Washington Post's Opinions section.