It has to do with how they clock or log latitude and longitude coordinates. ... an example, it pings every second it collects less data vs collecting every half a second.
... So you ask why are the apps not all using the half second vs the 1 second? Battery. For a true accurate reading it would have to be a constant ping and that would kill your phone very quickly on battery.
Ok, I get all that. As I mentioned in op, I never took any reading of my max. speed to b 100% spot on. I always assumed that any logged speed would likely b +\- a few mph. So I suppose the argument being made by detractors of these apps. Are the flat out claims of top speed without acknowledging THAT discrepancy?
Or are people claiming that these apps. are unreliable and inconsitantly inaccurate enough that ANY given speed is questionable?
Additionally, that still doesn't address my observation that similar apps used when I ride my MTB seem to B reasonably close to the milage & mph's logged with my bike mounted odometer! Again, usually anywhere within 3-5 mph. Any time I've encountered larger variences than that, they can usually b traced to signal loss or interference.
That level of accuracy is good enough for me to be reasonably confidant that I'm not making wildly inflated, bullshit claims for my snowboarding speeds. Are we arguing about split hairs here?