Pace Inaccuracies

[Whynotrun]

I've noticed this same discrepancy with watch, app and dashboard on pace. I've done 4 half marathons and training for my first full in April. Thinking I need to switch tracker to Garmin. What are your thoughts?

[vee]

Sounds like you aren’t using GPS. 

[Whynotrun]

I always have GPS connected to Fitbit as well as sync before and after running. GPS says connected when I push exercise and select run. Problem started when Google and Fitbit merged. 

[vee]

That is strange. So what does the mileage say and does the map look right? The pace should be determined by the distance. Or is the GPS not working right? Is it using your phones GPS or your devices GPS? I have an iPhone and have not converted to the Google account. My versa three cuts a few corners with the GPS that’s built-in so it makes it look like I’m a little slower. When I use a charge five with the phones GPS that seems more accurate maybe even a teeny bit longer! though both are close. I do really hate it when the distances off with the cutting corners and making me look like I’m slower! 
The Garmin should be more accurate with GPS though it might also cut corners. I have used both. 

[Triletics]

@vee when running, GPS isn't what determines pace and distance. It's not how it works on Fitbit.

@Whynotrun as a runner, I can tell you that Fitbit is not a runner's watch. It has the poorest support for running, is inaccurate and full of inconsistencies. It clearly shows that Fitbit doesn't understand sports tracking.

[vee]

Please enlighten. Everything I’ve read says they use GPS to determine distance when GPS distance is available. Without GPS they have to rely on stride length and steps. 

[Triletics]

@vee when running, GPS is too inaccurate to provide real-time data so manufacturers (not only Fitbit) use other sensors to determine pace and distance and correct it (or not, Fitbit doesn't seem to) with GPS data. If you export the GPS data from Fitbit running activity (TCX file) and measure that distance you'll find out that it's different from Fitbit reports. Also, skipping in place adds to the distance, too. Most of watches use multiple sensors (accelerometer, gyro, barometer, magnetometer) and GPS to make pace and distance as accurate as possible. Fitbit for that matter uses most likely algorithms it developed with first devices and it doesn't seem it applied any improvements. Then it shows results like my run today:

Also, the duration doesn't match what the web dashboard shows but that's something I have already used got to that in the Fitbit world nothing matches 🙂 In the table, the distance of 13.28km is purely based on GPS trackpoints from the exported TCX file (other fields like pace are only local for the last data points, they aren't averaged so can't be used to compare anything). In this case, GPS hasn't been lost at all (which is very rarely a case on Charge 6). This is 600m of difference. Not a small error (but usually, it's worse than that).