Because it distrusted the Labor Department’s unemployment statistics, the Federal Reserve — without any fanfare — started calculating its own jobless rate two years ago.

And the Fed’s calculation, called the Labor Market Conditions Index, or LMCI, shows that the US unemployment rate in February was 5.8 percent. That’s much higher than the 4.9 percent official jobless rate reported by the Labor Department.

More important, the LMCI explains a lot — like why Fed chief Janet Yellen is keeping interest rates exceptionally low despite the fact that the economy seems to have surpassed her jobless rate target. It also explains why she has suddenly backed off some of the rate hikes promised for this year.

As my longtime readers know, I’ve been investigating flaws in the nation’s unemployment calculations for years, including the fact that people who give up looking for work stop being counted as unemployed and that not all jobs are created equal.

For instance, that official Labor Department 4.9 percent unemployment rate jumps to 9.7 percent when you count people who are employed but can only find part-time jobs, as well as those who are jobless and have looked for work in the past year but not within the four-week scope of the latest survey.

What happens if you are so discouraged about finding a job that you haven’t looked in a year? Well, you don’t show up anywhere in the Labor Department’s unemployment statistics.

And in a time of deep economic crisis, a lot of people have fallen into this category and were conveniently considered “not in the labor force” by Washington.

The Fed apparently understood the failings of the Labor Department’s so-called U-3 unemployment rate — the 4.9 percent headline figure in February — which is the focus of the media every month.

So, in October 2014, the Kansas City Federal Reserve Bank quietly came up with the LMCI, a stew of 20 different government stats.

This includes: the official U-3 unemployment rate, the broader U-6 unemployment that was 9.7 percent in February, the employment-to-population ratio meant to capture those who haven’t looked for work in more than a year and still might want a job, the number of temporary workers, the level of new jobs reportedly created every month, and much more.

A source working on the LMCI explained it to me this way: If the Labor Department’s official unemployment rate is the temperature of the job market, the Kansas City Fed’s calculations take into account the windchill factor.

Nothing is perfect. The LMCI, for instance, assumes that the data it is using are reliable. But the old statistical adage still holds: Garbage in, garbage out.

For example, the Kansas City Fed isn’t checking for the accuracy of the data provided by Americans to Census Bureau interviewers.

I’ve already told you how some interviewers were cheating on these surveys — “curb stoning,” it’s called — by filling out responses on their own without interviewing the subjects.

And there’s the real possibility that people simple don’t tell the truth. Who wants to explain to a stranger, “No, I haven’t looked for a job. I’m a loser”? It’s easier to tell a lie.

Fed Chair Yellen did her usual shuffle around the truth during a speech Tuesday to the Economic Club of New York.

The US economy was doing just fine (even though gross domestic product grew at a paltry rate in the fourth quarter of 2015 and is worse in the first quarter of 2016): All our problems are being caused by economic weakness abroad (the “it’s the other kid’s fault” defense) and the labor market continued to improve (but she concedes there may be more “slack” than we think).

That “slack” — consisting of people without jobs — is probably coming from Yellen’s knowledge of the LMCI.

The Labor Department will announce the employment statistics for March on Friday.

The experts expect a gain of 200,000 jobs, down from the 242,000 reported in February. And they are also predicting the official unemployment rate will hold steady at 4.9 percent.

In case you are wondering, the Kansas City Fed will disclose its Labor Market Conditions Index for March next Wednesday — although you’ll have to find it on the website.

I’m not going to do my trick this month and guess whether new job growth will come in over the expected 200,000 level.

I’ve been nailing my monthly predictions but March is a tough one, so I’ll pass.

That’s because a lot of economic activity and hiring could have happened earlier than usual due to nicer weather around the country in January and February.

I also don’t want to guess because the Labor Department only adds a small number of jobs — probably around 72,000 — that it thinks, but can’t prove, are being created by newly formed companies. Unlike in most months, that amount is too small to have much of an impact on the headline number.

While both of those factors could prove to be a drag on employment growth in March, I’m not sticking my neck out on this one.