Inaccurate devices

[LewWagner]

Disconcerting study out of UK about the inaccuracy of many types of devices (to include flex)

Accuracy of Several Fitness Tracking Devices

[Dominique]

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@LewWagner wrote:

Disconcerting study out of UK about the inaccuracy of many types of devices (to include flex)

Accuracy of Several Fitness Tracking Devices

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They missed the point of a 24/7 activity tracker, which is not maximum accuracy for any single activity (how much time people spend everyday packing their groceries anyway?), but providing a decent estimate for the whole day. If you get 10-15k steps everyday, it won't matter much if your Fitbit Flex overestimated calories burned when typing on a computer. Chances are they will be compensated by some other activity where it underestimated them.

[LewWagner · Accepted solution]

If a tracker is "off" on any given activity, how cumulative is that error over time?

I specifically like to see how I am doing on particular exercise sets so that I can compare over time if I'm slacking off or improving.  I'd like to think there is some level of accuracy.

I've posted a link in an earlier post showing that Fitbit Zip and I think Flex or Force or One was used.  They were among the top two devices (of about 5 or six I think) that were within 10% accuracy.

Granted, as long as the device is consistent, it might be under-reporting or over reporting your cals and other metrics, but will it be "close enough" to give reliable stats?

Heck, the GPS sensor in my TomTom GPS Sportswatch shows variations in distance (slightly) over the same path I take around the neighborhood.

I like the One, and the newer Charge and Surge HR devices.  I've bought a Charge HR for my wife and when they sufficiently "de-bug" and "beta-test" the Surge HR, I'll probably get one.

[Heybales]

I think you'd probably want to use a different measurement method to decide if performance is improving or going down on staying the same, rather than calories.

Becaues even at the same weight, if you kept running the same pace, you might think you are maintaining, but the heart as a muscle becomes more efficient, along with muscles in using oxygen.

So the HR goes down doing the same pace same weight. Calories in reality burned are the same.

But a cheaper HRM is going to say less calories burned.

I suggest pace and HR together will give better view. If going faster and same HR that used be seen going slower - you've improved.

Weights should be easy, increasing reps or weight should happen over time.

Very true on GPS accuracy, even if it says 10 ft/3 m, that's in a circle and could bounce from one side to the other, usually going around corners, changing the distance enough.

Oh, pretty brave walking in the water there!

[zeegeezer]

I have to agree that the Charge is pretty inaccurate. It's recording several thousand steps more per day than I actually walk. Sitting in my office chair today, typing, The Charge has recorded almost a thousand steps; I doubt if I've taken more than 100 over the course of the day.

I admit that it's nice to be told every day I've done my 10,000 steps; but then I have to think I've really only done maybe 8,000 steps.  And I feel annoyed.

[RalfRim]

Got my fitbit 2 days ago. I'm very active but I was surprised how easily I got to 10k steps. 2nd day I had 15K that made me suspecious. So I looked at my current stats and just moved my hand left and right and up and down and voila......28 steps without having moved one inch. This thing is completely useless what a joke

How come nobody ever figured this out. Yes it makes you feel good when you "reach your goal" but it's all wrong data.

Returning it tomorrow

[bdaniels04]

@RalfRim 

Do you have your Fitbit settings set for the correct wrist placement? I noticed right after I got a new phone that I was getting a lot more steps in than I should have and when I went into the app settings, the app when it downloaded had defaulted to the non-dominant hand placement. Once I changed that to dominant (I have a hard time wearing it on my non-dominant wrist), it corrected the issue. It will still sometimes pick up a *few* arm movements as steps, but very few. See if that solves your issue.

[RalfRim]

Thanks for the tip. I will try that.

[redred1234]

There are products out that go on your shoe that you insert your fitbit into, and i must say i love it! I purchased mine at Best Buy for $5 made by Griffin. This might change your mind on accuracy since it is truly based on the steps taken and not hand movements.

[Heybales]

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@redred1234 wrote:

There are products out that go on your shoe that you insert your fitbit into, and i must say i love it! I purchased mine at Best Buy for $5 made by Griffin. This might change your mind on accuracy since it is truly based on the steps taken and not hand movements.

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Have you actually done a test walking that way?

Because that is incorrect that it is trying to get steps from hand movements.

It's not - it's trying to detect impact of steps taken DESPITE hand movements. Which can be tricky something if you have a strong grip on non-moving object (shopping cart) and therefore impact of steps can't be seen. Or your hand movements are such they appear like light steps (since little distance, not much calorie burn assigned either)

The problem with walking and on the shoe placement though is bad too.

The ability to get accurate assessment of impact and hang time of body before impact (the formula's are assuming on body, not foot) are thrown off.

Usually when people step, there is no impact on other foot that is not landing.

So if you have device on right ankle, and during a normal stride while it's at back about ready to push off, the left foot has already had impact at front.

What I've tested and others have reported, depending on how much of a toe walker you are, is about 1/2 the steps being seen.

Plus the other measurements are off.

Even when running, though it'll see all the impacts due to nature of each foot being off the ground, it'll still see some other stats incorrectly - so now distance is off, and that means calories is off.

It's the same way there are holders out there for taking a wrist unit to the body - but again, the formulas were tweaked for being on the wrist, not the body, and certainly not the foot/ankle.

So just wondering if you have tested walking 100 steps, and confirmed the device increased that much?

And have you confirmed distance?