I’m quoted in a Sunday Washington Post story on missing frequent flyer miles. Michael Shapiro goes looking for why frequent flyer miles we earn don’t always post to our accounts.

Most of the time it isn’t the fault of the airline or hotel whose miles you’re accuing. Generally they have to be told what miles to credit by the partner you earned the miles with. The most frequent reason miles don’t get posted is because you haven’t given the number to the partner in the first place.

Sometimes, of course, that’s not your fault. I’ve had American Airlines reps not know how to enter a Mexicana Frecuenta number. And websites like Orbitz don’t even give you a chance to enter partner frequent flyer numbers (this feature is one thing I prefer about Expedia).

There can be glitches in the way data is transferred. Some partners don’t report miles very often, or partners that actually send over data on tape have problems with the medium. But usually it’s as simple as not entering a number in the first place. (Online shopping points can be a bit trickier, relying on web technology and cookies for tracking information.)

It’s rarely the case of an unscrupulous partner who just doesn’t want to pay for the points (though this does happen once in a blue moon, especially with smaller merchants or vendors going out of business).

My best advice is to track the miles due to you in a spreadsheet, and follow up when points haven’t posted in the correct amount of time. Then keep following up. Relentless pursuers of miles get the credits. While it may seem annoying and hardly worthwhile, keeping on top of miles adds up and yields the award tickets at the end of the day.