Are fitness trackers unreliable crap?

Nick Bilton of The New York Times had a post last week titled "For Fitness Bands, Slick Marketing but Suspect Results". Wow them's fightin words!

He starts with an anecdote:

"My Nike FuelBand read lazy. My friend’s read fit. But we had done essentially the same thing. We spent the day walking around San Francisco together — the same number of miles, same number of hills — but for whatever reason, our FuelBands were out of step. His registered thousands of steps more than mine did."

He then concludes:

"That’s the uncomfortable truth about many of the fitness wristbands you see people wearing. They don’t really work — or at least not as well as their manufacturers would have you believe."

Do fitness trackers work?

According to my previous post, they do:

Finally, Consumer Reports performed perhaps the most definitive study that "combined step count accuracy for walking for five minutes on a level treadmill at 3 mph, using an elliptical exerciser for five minutes, walking up and down several flights of stairs and picking up toys from the floor." They tested 6 trackers and gave all of them either an excellent or good score for step counting accuracy.

In that post, I also cited the study by Jim McDannald for the technology website Wirecutter who tested 4 trackers over a 6 day period and plotted the steps per day. The number of steps were within 5-10% for all the trackers.

Yet when interviewed by Mr. Bilton the same Mr. McDannald states: “Even a cheap pedometer is more accurate than these wristband trackers,”

So who is right and which Mr. McDannald should we believe?

For now the evidence from multiple studies outweighs Mr. Bilton's anecdotal story although some of the discrepancy could be explained by the difference between "field studies" versus more carefully controlled studies in the lab. However, it is important to point out that cheaper pedometers do indeed count steps using an accelerometer in the same fashion as more expensive fitness wristbands; the product differentiation arises from the bells and whistles (e.g. flashing messages, health data analytics and cloud storage, communication with your smartphone or computer, etc.) provided by the higher-end fitness bands.

Finally, it could be that Mr. Bilton had a faulty FuelBand; after all Nike is discontinuing this product line.

Figure 1. Are fancy fitness trackers no better at counting steps than a $3 pedometer?