Aria 2 display and sync weight different

[troutteaser]

Why does my Aria 2 display my weight and body fat numbers different than what gets synced to the App?  It's not a rounding error.  For instance the Aria 2 display might say 166.6 pounds and 17.4% body fat, but after syncing to my iPhone the Fitbit app will display 165.4 pounds and 17% body fat.  I was told some months ago that this is a known issue.  If I had known this when I was looking for a scale I wouldn't have bought the Aria 2.  What is the status of fixing this?

[troutteaser]

Yeah, it appears Fitbit is not very good at addressing their customers concerns.  Maybe it's because they don't care now that Google owns them.  I also I find the scale gets easily confused between people of similar weights.  I complained about this as well to Fitbit and was blown off.  I would have returned the scale if I could have.  I wish I had spent less money and bought a different scale.  Live and learn!

[TedL]

What difference are you seeing? I get a 0.1 pound difference, which is
hardly “a completely different number.”
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[Carijk]

Not the number the scale reads. Which is what I paid for and expect to see on the app. Period. The old scale could do it but the new one can’t? That’s unacceptable.

Sent from my iPhone

[TedL]

You didn’t answer my question. How different are the two numbers? I get
something like the scale would show 159.9 and the app 160.0 (or vice versa;
I forget whether the app is 0.1 lbs higher or lower than the scale.)
Roughly half the time they read the same, the rest of the time they differ
by exactly 0.1 lbs. This is annoying only because the scale itself is much
more accurate than that — the standard deviation of repeated measurements
is something like 0.02 lbs (I forget exactly what the number is and I’m
away from my computer that has my records.)
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[LizziGleason]

I agree - When you pay that much for a scale, both the app and the scale should match - no matter the difference.  I also had the Aria 1 and it always matched... then it died two years later.  I bought the Aria 2 and a couple weeks into it, I realized that the scale and app were not matching, customer services didn't respond, and there were a lot of complaints.  I took it back and go the Withings scale and absolutely love it!  It was cheaper and has so many more options!!!  Good luck!

[TedL]

You didn’t answer my question. How much difference is there? I agree, as
best I can tell, no-one from Fitbit has attempted to confirm the problem,
even though several of us have reported it. I don’t remember if I had the
same problem with Aria 1, but that was sufficiently inaccurate it wouldn’t
matter.
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[Carijk]

I think I’m going to take mine back too. Glad to know it’s not just my scale though! I will have to look into that one. Thanks!

Yes .1 scale said 179 app said 178.9. continuously and over time, just frustrating and unnecessary.

Sent from my iPhone

Moderator edit: merged reply

[TedL]

All that fuss over 0.1 lbs? Yes, it’s an annoyance, but I have a hunch why
it is happening. My guess is this. Internally the scale reads your weight
as something like .75 volts from a transducer whose output varies with the
weight (heavier, a higher voltage; lighter a lower one). The software in
the scale converts that to pounds or stone or kilograms. When the weight is
sent to the Fitbit server it is sent as the raw data (volts) and is
converted to pounds or kilograms or whatever by software in the server.
Different people wrote that software, perhaps even with a different
programming language. They used different rounding or truncation rules,
possibly even out of their control (without a lot of work.) Keeping track
of 45 weighings over the course of several days (repeating most of them a
half dozen or so times at the same time) I observed that about 15% of them
had exactly the same weight on the scale and in the app; the rest were
exactly 0.1 pound off. Over the period in question my weight varied about
1.5 pounds, so the scale was, even with the 0.1 pound error, reading
sufficiently accurately to show even that small change. (The actual
measures show a standard deviation of 0.088 pounds, which is pretty **ahem**
good but not much better than the 0.1 systematic error.) I tried to figure
out what algorithms might give the observed pattern of 0.1 pound
differences, but couldn’t. I agree it would be nice for Fitbit to explore
the problem and see if my guess as to what is going on is right, and to
correct the problem, but I can also see that with limited resources why
they wouldn’t bother.
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[brantgurga]

I think you are probably right. Sometimes the app/device say the same.
Sometimes off by 0.1. That doesn't mean Fitbit shouldn't acknowledge the
problem though. The instead respond with dismissal as if we make it up. I
don't think that's the case. Ideally they should fix it. Minimally they
should acknowledge it and say yep it's an issue and we have no plan to fix
it. It'll not be more the 0.1 pounds different when different.

Moderator edit: personal info removed

[VivienneS]

I weigh in kg. Mine is also syncing 0.1 kg out with the App always showing higher than the scale readout. It happens with the body fat readout sometimes too. 

[Freyja927]

Mine is in kg. It seems to sync correctly at the time, then later it changes, goes down 0.1kg and the body fat percent disappears. 

Very frustrating. 

Only been doing it for about a week and I've had the scales (Aria 2) for months. 

Tempted to change it to pounds as 0.1lbs is mostly negligible, but 0.1kg is a bit more of an issue.