Difference between data from CMPedometer and HealthKit

Question

The following chart lists my step data from HealthKit vs. the CMPedomoter class:

    HealthKit   CMPedometer  difference
1   2710        2681         -29
2   2569        2580          11
3   2367        2312         -55    
4   1326        1311         -15
5   2728        2711         -17
6   860         886           26
7   6293        6299           6

There is a slight difference each day between the two. Does anyone know why this might be the case? No other app is writing step data currently to this device.

Plethora

Do you have any other pedometer or sport watch syncing with your phone? – Gutta

No other pedometer or device is syncing with this phone. What is curious to me is that some days show a higher step count while others are lower. – Plethora

Maybe it is other app updating HealthKit? Try to turn all other apps updates to HealthKit off and see if the difference go away – Gutta

No other apps are allowed to write data to HealthKit per the sources tab in the Heath App. – Plethora

I found some thing interesting in this link, you should take a look punchkickinteractive.com/blog/2014/11/17/… – Gutta

Answer 1

Problems is that all steps has Float value so for example in real could be:

time - pure data - after round
1:05 - 0.95 steps - 1 steps 
1:15 - 1.25 steps - 1 steps 
1:25 - 14.75 steps - 15 steps 
1:45 - 1.95 steps - 2 steps 
2:05 - 4.65 steps - 5 steps 
2:15 - 11.25 steps - 11  steps 

and if you sum it like integer you will get 31 steps and if you round it before you will get 35

also had this issue when synch data from pedometer and health kit

Belgium

also they are not always same, cause pedometer its like another app that write data to HK database. And no one knows how exactly it works(except Apple developers, they have source code). – Belgium