Step tracker accuracy within 25% range on different days!
On a short day of steps. This is without a run, working at a desk, and mostly being sedentary. The Halo tracked 8% more steps than the Apple Watch. This isn’t too much variability between the two, and might be explained in part because the two were worn on different hands. The Halo was on a dominant hand (used for writing and mouse clicks).
On a day with a workout, in this case a single 5 mile run mid day. Here the two devices were much different, with the Amazon Halo band measuring 25% more steps than the Apple Watch. This is the largest difference observed ever while wearing the two devices simultaneously.
The final day compared here is a big one. The Halo band measured 12% more than Apple Watch. The day included two runs and a long walk, or a total of around 14 miles of activity in addition to steps taken meandering about the house.
Step trackers are great, however this simple experience shows an important point. The absolute step count may not be as important. In either case the goal is to track, mostly, to encourage staying active. Regardless if the step tracker is getting you from 8000 up to 10,000 steps that’s great!
It doesn’t matter if you don’t actually take 10k steps. Even if it’s really only moving from 6k steps to 8k steps, but telling you it’s 10k, that’s still better than 6k and not knowing!
What effects step count?
It’s no surprise that step trackers don’t return the same number every time. Each of these works on an algorithm that finds how much the device moves, using an accelerometer sensor. That signal from the sensor then has to be trimmed for noise. Raising your hand over you head, swinging an arm during a run, or moving your hand while grilling a mouse all cause some signal to the step tracker. Sometimes the signal might not get counted right.
Step counts should be expected to vary based on the hand they are worn on. They could be effected by the type of walking you do (up or down hills, hiking over non steady surfaces) too.
In this simple experiment it was encouraging to see that although step trackers may not be accurate, they are precise. Precision should imply that the step tracker is accurate, when compared to itself, even if it’s not a 100% representation of a “step count”. In this case you can think of step trackers just as activity trackers that happen to correlate nicely to the number of steps you took. In part this is just naming conventions.
As we get more ways to track steps we have seen similar results. Ultimately, the accuracy of the individual step tracker is not the one feature to rely on. The other features of an activity tracker, it’s app interface, and the form and style, may be much more important in deciding which device to make your daily choice.