It’s lunchtime in downtown Washington. How do you know where to go for a delicious meal at a fair price? Or better yet, how to avoid a bad one? An economist can help.

The city’s dining scene still falls short of the quality of Chicago or San Francisco, much less New York or Los Angeles. Nonetheless, it is possible to eat very well here, provided that one understands where the quality is distributed. As a longtime economist who has written a blog and a book on the economics of food, I have been studying and indeed living the economics of our local dining scene for more than two decades.

The key is to understand the culinary problems, and then figure out how to work around them. Let’s focus on the workaday crowd’s options downtown, which I will define as most of Northwest but not the top parts of Wisconsin or Connecticut.

First, much of downtown has an underdeveloped public street life. Washington empties out by early evening. It is easy to live in the Maryland or Virginia suburbs, which drains the city of potential energy, and this afflicts the daytime hours, too. Even U Street and Adams Morgan are lackluster by the standards of major global cities.

Second, a lot of Washington doesn’t have a very good public school system. Education-conscious Asian immigrants usually prefer the suburbs and that means D.C. proper doesn’t have a lot of first-rate Asian food.

Finally, the highest-status people in town — the politicians — usually have, or at least feel inclined to demonstrate, remarkably conservative taste in food (President Obama has been a welcome exception). Finance professionals in New York and entertainment moguls in L.A. set a flashier and more innovative tone for their favored dining-out places.

Washington does have its strengths. Namely, the city has a lot of high-income, highly educated transients. It attracts visitors, tourists, young interns and other workers who do a brief spell here but have no intention of staying. Because they come from all over, transients support food variety.

Yet transients also encourage restaurants that build up their reputations rapidly to appeal to a busy, underinformed and sometimes underseasoned audience. Those same restaurants also tend to fall in quality relatively rapidly; even when they don’t go outright bad, they usually descend into the realm of the ordinary.

Be the early bird

The key is to hit these restaurants in the “sweet spot” of their cycle of rise and fall. At any point in time Washington probably has five to 10 excellent restaurants; they just don’t last very long at their highest levels of quality.

Here’s how it works. A new chef opens a place or a well-known chef comes to town and starts up a branch. Good reviews are essential to get the place off the ground, and so they pull out all stops to make the opening three months, or six months, special. And it works. In today’s world of food blogs, Twitter and texting, the word gets out quickly.

Which restaurants have held this crown? A partial recent list would include The Source, Zengo, Sei, Palena, Oyamel, Hook, Equinox and Central Michel Richard, among many others. They all had their moments of glory.

Which places are peaking right now? I would nominate Little Serow and Rasika West. I have been seeing the right kind of stellar reviews for Mintwood Place (I have yet to visit). I had an excellent meal at Fiola a few months ago, but I’ve already heard reports of quality decline. I’ll continue to monitor the situation.

Avoid the beautiful people

Through information technology, we have speeded up the cycle of the rise and fall of a restaurant. Once these places become popular, their obsession with quality slacks off. They become socializing scenes, the bars fill up with beautiful women (which attracts male diners uncritically), and they become established as business and power broker spots. Their audiences become automatic. The transients of Washington hear about where their friends are going, but they are less likely to know about the hidden gem patronized by the guy who has been hanging around for 23 years, and that in turn means those gems are less likely to exist in the first place.

Most of these places remain above average in food quality, but they stay pricey or become even pricier. They are not incredible bargains, and they lose the edge and novelty and obsession with quality that defined their early days.

So here’s the key to eating well downtown: Find places in their golden opening, three- to six-month periods, noting that the first few weeks may involve working out some kinks in the kitchen. Figure most of these places will not stay excellent for more than a year. Go to the ones you like, as often as you can.

Leave when the magic is gone

And here is the clincher: Once you have one “pretty good but no longer special” experience at a relatively new restaurant, stop going.

Forever.

Weep but don’t look back, unless you hear consistent reports that it was truly an aberration. Most likely the magic is gone. Look around for the next excellent place because I promise you there will be one. Cultivate culinary disloyalty in yourself. That is more valuable advice — for Washington at least — than any restaurant recommendation I might send your way.

That may sound ruthless, but the odds are in your favor. We humans have what behavioral economists call a “status quo bias” for sticking with what we know and love. That bias makes sense when it comes to how we treat our friends and family, but it is a mistake to apply it to restaurants. The restaurant, of course, does not have the same loyalty to you.

If it makes you feel better, think of it this way: If more diners behaved in the manner I am suggesting, restaurants would have to keep their standards higher for a much longer period of time.

Don’t ignore the old standards

New York, Chicago and San Francisco are all more likely than Washington to have consistent, excellent restaurants that appeal to a solid, long-standing base of regulars; think Union Square Café in Manhattan. That said, the phenomenon of excess trendiness is spreading to restaurant markets across the nation, and in this regard you can think of Washington as a rather unfortunate forerunner of broader national trends.

Counterintuitively to many foodies, some of the better expensive meals downtown can be found at the old standards, such as The Palm or Prime Rib; they rely on regulars rather than on trendiness. Those restaurants are for my taste not as good as the top trending places. The menus at these establishments are for many diners less interesting and the prices are quite high. Still, if a meal were gifted to me, I probably would enjoy it more at either of those spots than at the average, watered-down trendy Washington place. You can do worse than to be treated to Morton’s, even if you’re not keen on steak.

Often knowing how to order is as important as choosing the restaurant.

●If you are in an ethnic restaurant, look around to see what the other diners have chosen.

●When speaking to the waiter and asking for advice, signal your knowledge of their country, culture and cuisine (prepare in advance if need be), and your request for information about the best menu items will be taken more seriously.

●At fine dining establishments, look for staff who will offer a firm opinion as to what is best, rather than responding with something like “Everything on our menu is good!”

●If there is a fixed-price menu for lunch, usually it is neither the worst nor the best items but rather those least likely to offend the mainstream patron. Aim to do better.

Another tip for eating well in downtown Washington is to show up at 5:30 for dinner, if you can, or at 11:30 for lunch. The service will be better, and there is virtually no chance of experiencing a kitchen breakdown, which is pretty common on a Saturday at 8 p.m. Oyamel for one is a much better restaurant in its off hours, and kitchen breakdown during peak hours is a common complaint about El Centro D.F., the Richard Sandoval establishment.

Don’t overlook gas station fare

Choosing the best ethnic food downtown is tougher, as high rents and tight space keep out the kinds of gems we find so frequently in the Virginia and Maryland suburbs. A reigning principle of good ethnic dining is to look for clusters of restaurants of the same kind, as we find with Vietnamese restaurants in Falls Church or the numerous Korean places in Annandale. The D.C. cluster of Ethiopian restaurants on 9th Street qualifies (I’ve enjoyed every single place in that row). But it is hard to find comparable examples around town.

Dupont Circle, Adams Morgan and U Street have not succeeded in generating first-rate clusters of particular ethnic cuisines. Dupont is now gentrified and expensive, while the other two neighborhoods bring too much automatic foot traffic, most of all from the young, to enforce high-quality standards on ethnic food. The population of Washington is in the range of a mere 600,000 people, and so few ethnic groups produce a large enough local critical mass of diners to support an informed level of taste. Washington’s Chinatown has been a food embarrassment for a long time, but you will find a thriving Chinese community, along with quality Chinese restaurants, up in Rockville.

Good ethnic food in D.C. is a matter of spotting the isolated outposts, usually in neighborhoods good enough to attract some visitors but in unexpected nooks and crannies. My favorite ethnic D.C. dining at the moment is Keren, at Florida Avenue and 18th, an Eritrean place under new ownership.

The area on and near 14th Street has promise, and I enjoy the Uruguyan sandwiches at Fast Gourmet at Lowest Best Price Gas, 1400 W Street. Yes, that is attached to a gas station. Get the chivito, a sandwich with beef, ham, mozzarella and escabeche.

Ethnic places don’t usually go through the boom-and-bust cycles of the trendy restaurants, unless it is a deliberately trendy and expensive ethnic place. Most ethnic spots already are appealing to an informed clientele, and the restaurant is likely to stay good as long as the proprietor sticks around.

To be sure, for D.C. ethnic food there are also the food trucks, which flourish when the law leaves them free to operate. Nonetheless, food trucks are as much a sign of underlying weakness as of strength. Think of them as proof that zoning and rents won’t allow for much nearby good, quick, sit-down, cheap ethnic food. In any case, the downtown food trucks do a much better job for lunch than for dinner.

If all else fails, gas up the car

Sometimes D.C. residents dream of going to the suburbs by Metro for first-rate ethnic food, but that’s harder than you might think. The restaurants near the closer Metro stops (think Bethesda or Clarendon) tend to be the most like ethnic food in D.C., with some quality expensive places, such as the Mediterranean food at Cava, but overall those sites tend toward the mainstream.

The best suburban ethnic food is far from the Metro stops and high rents, so think about travel by car or ZipCar or even cab (you may very well earn the cab fare back on the cheaper cost of dinner).

Eating “pretty well” in downtown D.C. is easy. Eating truly well, especially for your money, is a challenge. The options are there, but they require a bit of urban knowledge, some economic reasoning and a willingness to turn somewhat ruthless. Keep in mind that your discipline in choosing the best will improve the food options for everybody else, too.

Cowen is professor of economics at George Mason University and author of “An Economist Gets Lunch: New Rules for Everyday Foodies.”