Northrop Grumman Corp.’s decision to move its headquarters out of Los Angeles, in and of itself, is no biggee.

We’re only talking about the loss of 300 jobs. That’s less than one-hundredth of 1 percent of all payroll jobs in Los Angeles County.

What’s more, Northrop’s departure doesn’t necessarily say anything derogatory about L.A.’s relative business climate. Northrop’s explanation that it wants to move to the Washington, D.C., suburbs to be close to its prime customer, the Defense Department, is perfectly plausible. It needs to be there; it didn’t say it’s itching to flee from here.

But rather than focus on the decision of one company to move, it’s far more instructive – not to mention important – for the community to look at the decisions of a bunch of companies. In other words, the Big Picture. Are more companies moving out or moving in? Are companies that are born here staying here and growing here? One the whole, are we thriving economically or slowly dying?

Alas, the big picture may make you squirm.

Just take a look at big-company headquarters. When the Fortune 500 list came out last spring, Los Angeles County was home to 14 companies. Metro Chicago has twice that many; Houston nearly twice. Smaller metro areas such as Minneapolis, Dallas and even downtrodden Detroit have more than Los Angeles.

Since that list came out, DaVita Inc. announced it was moving its headquarters from El Segundo to Denver partly because of the lower costs there, and last week Northrop announced its departure. That brings L.A. County’s total down to 12. By the way, L.A. County had 17 on the Fortune 500 list in 2007.

OK, but that’s only big-company headquarters. How about medium and smaller companies?

I’m afraid the picture there is even worse. If you read the Business Journal, you may recall an article in July (and a Comment column) that explored the fact that there are fewer payroll jobs now in Los Angeles County than 20 years ago. In fact, the number of payroll jobs hit a peak in late 1989, and we never once saw that many jobs here again – despite a couple of economic booms after 1989 and a big influx in population. (There was, however, a big growth in freelance and other informal, nonpayroll jobs after 1989.)

That tells you, on the whole, sizable companies that offer payroll jobs aren’t moving here. Or, if they are here, they aren’t staying here or expanding here.

But there’s a problem with these big-picture stats: They anesthetize us with broad numbers that lack precision. Exactly what companies are moving out? If we can’t point to any concrete examples, the numbers can seem like a jumble of abstractions. We have trouble believing what the numbers are telling us. There’s a tendency to click them off.

And that’s where Northrop’s decision becomes important. We can point to its headquarters, so long in Century City, and say, “There. That one. That’s the fourth biggest public company in Los Angeles County, and it is moving its headquarters.” It is the concrete example that illuminates the broad trend. Those academic stats and trends now have real people, names and a company attached to them.

In and of itself, Northrop’s move is not significant. Its importance lies in its role as symbol of the Big Picture, as poster child for the disease. And if Northrop’s move turns out to be the incandescent moment that finally prompts decision-makers to try to correct the problems that bedevil the business climate here, then Northrop’s decision will turn out to be a biggee, indeed.

Charles Crumpley is editor of the Business Journal. He can be reached at [email protected].