Had a note awhile back from the folks at Valencell, a company that develops biometric sensor technology. To be honest, I hadn’t heard of it until that email, but there no doubt are tons of other companies I’ve never heard of either!

Anyway, I asked if Valencell’s president and co-founder, Steven LeBoeuf (who has a doctorate degree in electrical engineering) could offer a few tips of what to look for in a fitness tracker. He was happy to comply. So if you’re NOT one of the millions and millions who own one — or you are and wonder whether you’ve done enough homework — read on:

Think beyond the wrist. It’s not as accurate a place for continuous heart-rate monitoring during exercise, he says, “because the wrist generates unwieldy fake readings due to motion artifacts such as skin motion and footsteps.” The ear, he says, is the best place. Wow! That’s news to me.

Think validation. Has the product been through independent validation for accuracy against gold-standard benchmarks?

What does that mean? That you should check the manufacturer’s website to see if the product has been tested “against gold-standard benchmarks, with interval testing on a treadmill, both indoors and outdoors,” he says. Plus, the testing should have been done on a decent number of people who are various ages, races and genders.

Match your wearable to your need. Sounds obvious, but not everyone buys a tracker for the same reasons. Maybe your goal is to get better at your current workout regimen or merely to walk those magical 10,000 steps a day.

Will it accurately measure calories burned? If you want to track calories burned during exercises that don’t involve footsteps such as those you’d do in a gym, you’ll need an accurate heart rate monitor or another type of continuous biometric monitor to capture your body’s exertion where pedometers cannot.

This article originally appeared in the Dallas Morning News