Service levels, you’ll recall, are two-part measures. They define a minimum threshold of acceptable performance and tally how often a service provider meets or exceeds it.

Enter the Pew Research Center for the People & the Press. In an excellent example of service levels in action, it defined a minimum threshold of acceptable knowledge of current events –getting two thirds of a questionnaire right (sample question: Who is the current Vice President of the United States of America?).

Then it tallied how many of those surveyed met the threshold.

Pew found, perhaps unsurprisingly, that those who watch The Daily Show and The Colbert Report on the Comedy Channel tied regular newspaper readers for top honors (54%). Those who watch Fox News met the standard 33% of the time, outperforming only watchers of network morning programs. Draw your own conclusions.

It’s tempting to blame this mess on intellectually lazy Americans, Katie Couric, Roger Ailes, or all of the above. Temptation being what it is, I will.

Underneath the symptoms, though, is a challenge you and I face every day as we deal with vendors, staff, managers, vendors, information outlets, colleagues, and vendors in the workaday world of information technology: The challenge of seeing what isn’t there.

To illustrate the point, go back to last week’s column, which described Factcheck.org’s critique of a current U.S. Chamber of Commerce ad. The ad provides an alarming statistic — that lawsuit abuse costs your family $3,500 per year.

I received quite a few e-mails challenging my statement that the U.S. Chamber … well, I said it was lying. The e-mails pointed out that the Chamber’s math was perfect. Lawsuits did cost $235 billion in 2005 and that this does come out to $3,500 per family, if you assume an average headcount of four (bad assumption, by the way).

The problem with the ad isn’t what it said. It’s what it left out — what isn’t there. It left out:

• How the Chamber defines “lawsuit abuse” (apparently, it’s “filing a lawsuit for any reason at all”).

• What fraction of all lawsuits falls into the “lawsuit abuse” category (close to 100%).

• How those who paid the legal fees and fines managed to transfer their costs to your family (and wouldn’t that make for a popular seminar?).

It’s far easier to deceive through omission than through falsification. Omission is far harder to spot.

In your professional capacity you’re inundated with product specifications and performance statistics, staff reports and recommendations, project proposals and justifications, all trying to persuade you to do something or other. If you’re like me you’ve become adept at skimming them to get the gist of what they’re trying to tell you.

Gist is a useful substance, right up there with beef jerky and Maxalt. It has its limitations, though, and top among them is that gist doesn’t help you spot what isn’t there. Quite the opposite. Gist is for understanding what someone is trying to tell you. As a result, it helps them conceal much more than it helps you reveal.

If there’s a magic formula for spotting what isn’t there I’m not aware of it. I do have favorite examples. Here’s one:

Imagine you asked a vendor if HP supports Vista for its 2840 color laser multifunction device (to take an example at random — that I happen to own one is sheer coincidence). Imagine the vendor answered in the affirmative.

The answer would be true. It would also be seriously deceptive. You can get a 2840 driver on HP’s website … which works for USB-attached devices but not network-attached ones. You can also download HP’s admirably conceived Universal Print Driver (UPD). It lets you print to the 2840 through either a USB or a network connection.

But only in black and white, and it doesn’t support the scanning function.

Phrasing your question to be in a position to accurately evaluate the product is something of a challenge.

How do you spot what’s missing? First, don’t skim — read carefully. Second, apply your experience. Think about all the ways you’ve been deceived in the past, look for parallels, and ask about them.

And third, don’t try to be clever. This question isn’t at all clever: “Here’s what I’m trying to accomplish. How will your products help me do it? Tell me step by step.” It might not be clever, but it gets the job done.

Of course, to ask this you do have to know what you’re trying to accomplish.