Home Fit Gear Reviews Is Your Fitness Tracker Accurate? New Tests Don’t Think So

Is Your Fitness Tracker Accurate? New Tests Don’t Think So

by Erika Nicole Kendall

Photo credit: Kazuhiro Keino/Flickr

From CNN:

The UPenn study recruited healthy adults who agreed to walk on a treadmill, tethered to 10 popular applications and devices by companies such as Fitbit, Jawbone and Nike, while an observer counted steps using a tally counter.

They found wearable devices in general were less accurate than the smartphone apps. The most accurate devices, according to the study, were the Fitbit Flex, One and Zip. One device, the Nike FuelBand, reported step counts more than 20% lower than observed; Nike did not respond to CNN’s requests for comment.

Despite the potential these devices have to get us up and moving, not very many of us have them, compared with mobile phones. A leading market research company says one in 10 adults in the U.S. own trackers, while nearly two-thirds of American adults own a smartphone — and new technology has enabled these devices to easily track physical activity and other health behaviors. [source]

When it comes to affordability, a $5 app that’s really worth the coins in terms of accuracy and functionality, in comparison to a $300 watch that’s equally accurate but more expensive, makes a huge difference.

What’s more, but when the most expensive device is the least accurate according to the UPenn testing, what does that say about how spending “more money” doesn’t require “better quality?

From the Well blog:

The promise of these devices obviously relies heavily on their accuracy and ease of use. If the trackers tell us that we have moved more or less than we actually do, our responses may not be appropriate or ideal. If, for instance, the monitor says that we have burned more calories than we actually have that day, we may overeat and gain weight. If, alternatively, the monitor says that we have taken fewer steps in a day than we actually have, we may become discouraged, blame the device, throw it in a drawer and stop walking for exercise altogether.

Similarly, if a fitness monitor is difficult to program, requires frequent charging, feels uncomfortable or is pricey, many people who might benefit from more exercise will avoid buying or wearing the thing. As the authors of the new study point out, only about 1 to 2 percent of Americans currently own an activity monitor, and many stop using the device within a few months of buying it. [source]

In other words, these items have to be a simple and accurate addition to our lives, or they’re useless.

So which ones were the most accurate?

Screenshot of the study's results

Screenshot of the study’s results

The pedometers worn on the waist produced the most precise results. The smartphone apps came in second, but they weren’t far behind.

The wrist devices were found to be the least precise. While the Fitbit Flex and Jawbone UP24 were fairly close to the actual step number, Nike’s Fuelband had the largest deviation. [source]

The downright cheapest option, you say? Wowzers.

Update: Someone asked me if this changed my view of trackers, or if it’d affect my use of trackers at all. For me and my Polar Loop, I’d have to say no – I don’t really use it for accuracy, as much as I use it as a reminder of how lazy I’ve been throughout the day (it buzzes when you’ve been stationary for too long – and whether or not I need to get up and get moving. As #bgg2wlarmy member Michelle put it on the FB page:

I’ve seen a lot of articles comparing these devices to smartphone apps (one calling users “idiots” for spending more money on the former). But I don’t carry my phone throughout the day. As for the accuracy, as long as it is consistent against itself, you can use it to compare your relative activity level over time, which makes it worthwhile to me.

Like any purchase, I think you’ve got to weigh it out with your goals and lifestyle.

IMHO, it’s totally okay to use these apps for something other than accuracy, like simply focusing on improving whatever numbers you get (presuming you consistently get numbers that are always the same percentage off every time.) Just keep that in mind when you’re looking at things like calorie totals for the day and, should you ever reach a plateau in your journey, let that be one of the first places you check you troubleshooting.

Are you using a tracker? If so, which one? How do you think yours fares?

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Angela (@MoveOverMS) February 23, 2015 - 7:18 PM

As the queen of “can’t have too many metrics,” I use several apps on my phone (Cardio Trainer is the one I use most frequently, but also Rock My Run and Samsung Health), my Fitbit One, and an Active Link from Philips, which is a tracker from Weight Watchers. I also have the Polar F7. Did I mention that I enjoy having metrics?

At one point, I noticed that my Fitbit was only recording about 2/3 the steps and mileage of Cardio Trainer, but once I realize that I’d inadvertently put in the step distance incorrectly. For the most part, though, since fixing the step distance, Cardio Trainer and Fitbit track consistently with each other, within 250-300 steps or so.

I do think, however, that the wearables on the waist provide the greatest accuracy, as they’re measuring steps, which involves movement from the core. Unless you use your arms when walking/running, it’s not going to be as accurate. And, of course, since I use a walker, that doesn’t happen too often.

Erika Nicole Kendall February 24, 2015 - 11:08 AM

That’s an *extremely* important point – those who use resources that aid with movement (walkers, canes, etc) aren’t going to be best-served by a wristband. I’m SO glad you shared this!

Biolobri February 23, 2015 - 7:20 PM

I have several thoughts on this.

1. Sure, I expect there to be a margin of error built in to the step counting. However, I’d rather have my tracker slightly UNDERestimate than over. I want some motivation to move. So, sure, the apps were closer to the total than the devices, but they all over-reported.

2. I used to use an app on my phone (between fitbits) – the problem I had was that Moves zapped SO much battery power from my iphone, it wasn’t a realistic option. I turned it off every time I needed to conserve power (which was often, considering how quickly it drained the battery). To me, and for my purposes, this makes it essentially useless.

3. I have the flex. I’m actually shocked that it is showing it to underreport. I always assume it’s overly generous with my movement since I move my hands so much when I talk, walk, etc. That said, I have set my daily step goal at 20,000 instead of 10,000. I’m not sure it’s necessary to double it, but it does motivate me to get there.

Viony February 23, 2015 - 10:33 PM

Too bad they didn’t track Polaris watches. Kind of weird too, aren’t they one of the more popular brands?

Erika Nicole Kendall February 24, 2015 - 11:04 AM

You mean Polar? I’m not familiar with a Polaris brand.

They didn’t track any of the brands that ALSO make heart rate monitors – Garmin, included. I’m not sure why either, but I’d be doubly curious about their accuracy as these are brands that specialize in accuracy for things like GPS, calorie burn, and the like.

I’d also have liked to see someone test the accuracy of the calorie burn figures some of these devices give, but I’ve not given it enough thought to figure out how they could do that.

Zenobia February 24, 2015 - 5:41 PM

I own the Nike Fuelband and I’ve noticed that it doesn’t record my steps when I’m on the treadmill but it records when I’m on the elliptical or when I’m lifting weights. From my own personal experience I’ve come to the conclusion that the Fuelband measures arm movement. I know that the Fuelband isn’t accurate and I’m OK with that. I’ve tried to use the apps on my phone but I find it more convenient to have this thing on my arm than to carry a phone around with me in the gym. I primarily use it for motivation. It’s my constant reminder to get up and get moving.

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