Why Aren't Fitness Trackers Actually Accurate?

By Gizmodo Australia on at

By Campbell Simon

There are dozens of different fitness trackers on electronics store shelves these days, and they all measure movement and energy expenditure and fitness in wildly different ways. But it turns out that no one tracker is more competent than another in actually accurately tracking your steps, even though the aggregate day-to-day data is what matters.

Say you aim for 10,000 steps in a day on your Jawbone fitness tracker, and you reach it. That’s great! But how far did you actually travel? How does 10,000 steps on a Garmin wristband compare? The BBC has had a look at the technology behind various fitness trackers, and was told by Jawbone and Fitbit technical gurus that it’s not actually about the actual figure recorded, but instead the day-to-day trend.

It’s a bit worrying to see the BBC’s finding, though, that between four devices — the Garmin Vivosmart, Fitbit Charge, Misfit Shine and Jawbone Up Move — there was a measured distance variance of a massive 23 per cent, and a gulf between the top- and bottom-measuring fitness trackers of almost 2700 calories. That’s more than an entire day’s calories for an average male maintaining his weight.

Misfit medical director Matthew Diamond was upfront with the BBC about the worst-kept secret of fitness trackers’ lack of “exact science”: “Variations in algorithms, the sensors used, the characteristics of the individual wearing the device, like height and gait, as well as wearing position, can result in observed differences.”

Because of that, fitness trackers fit into an interesting but odd niche — a Fitbit or Jawbone or similar fitness tracker will give you enough data for you to track your movement, and especially to track your progress, but that data is only valuable in camera and can’t be compared directly with a device from any other brand, or possibly even the same device worn by a different user. [BBC]

Fitness tracker image via Shutterstock


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