With all of the attention that online video gets—whether it’s the rise of Facebook FB as a video platform, or the growing phenomenon of “cord cutting,” and streaming or downloading—the traditional TV industry seems to have a bit of a chip on its shoulder. The latest Total Audience Report from Nielsen is clearly an attempt to soothe some of that agitation, with numbers that show broadcast television is doing just fine compared to digital viewing. But it takes more than a little smoke and mirrors to get there.

Online video often shows huge numbers, Nielsen’s senior vice-president of audience research Glenn Enoch says in the preamble to the quarterly report. But those numbers can be deceiving, he warns: “It may seem that tens of millions of video views is a much bigger number than a few million persons in the audience of a TV program,” Enoch writes. “But the TV number is expressing viewers in the average minute of the program,” while the online version is a raw figure representing everyone who saw even part of a video.

This is actually a fair point for Nielsen to make. Online video numbers are often inflated, in part to convince advertisers that there are millions of eyeballs just waiting to consume their ad campaigns. Facebook, for example, considers a video viewed if a user has been exposed to just 3 seconds of it.

If you compare apples to apples, says Enoch, the reach of a given TV program in the month or quarter in which it is aired “is far larger than the uniques attracted to the same piece of content online.” In other words, if the traditional TV industry played the same kind of games with viewership numbers that online sources do, it would blow online video out of the water, according to the Nielsen analyst.

Nielsen TV viewing chart
Nielsen Co.

A chart from the report shows that adult consumers in the U.S. still spend vastly more time watching television than they do on either their smartphones or PCs — about 36 hours a week for TV vs. 7 hours on a smartphone and 5 hours on a PC. Even the much-wanted 18 to 34 age group spends dramatically more time watching television than on the phone or the computer, according to Nielsen’s survey: 21 hours for TV vs. 10 for the smartphone and 5 for the PC.

So then everything is fine for TV, right? In a nutshell, Nielsen’s argument is that advertisers should care more about how long someone spends with a piece of content than just some raw eyeball number that shows who clicked through to a page. And there’s definitely some truth to that. At the moment, advertisers are involved in a kind of land grab for online video, and many of them are still paying huge CPMs (cost per thousand views) for videos that virtually no one watches.

At the same time, however, Nielsen’s survey fudges some of the numbers in order to make traditional television look better and online or smartphone video look worse. In the section where the company describes its methodology, for example, it says that when it calculates the total viewership numbers for smartphone video, it doesn’t include “video content available through apps/web where video is not the primary focus (Ex. CNN, Weather Channel, Facebook).”

That’s a pretty massive category of video to just leave out. Facebook, for example, says its users watch more than 4 billion videos every day, and that likely accounts for a fairly huge proportion of the video viewing for the 18 to 34 age group. Snapchat users watch more than 2 billion video clips a day, including some from outlets like CNN, but it’s not clear whether that’s included either.

It’s also worth noting that TV viewership as a whole continues to fall at a fairly precipitous rate of more than 4% year over year, according to a previous Nielsen report, and if anything that decline has been picking up speed. So perhaps TV broadcasters and advertisers shouldn’t allow themselves to get too complacent about the latest rosy-looking numbers.

Follow Mathew Ingram on Twitter at @mathewi. You can read his coverage of the media industry by going here, or you can subscribe via his RSS feed.