Monday, March 7, 2011

In which I question the accuracy of the Weight Watchers PointsPlus pedometer

I purchased the new Weight Watchers PointsPlus pedometer for two reasons:

1. I love that it automatically calculates how many Activity Points you earned. No more over- or underestimating!

2. I love gadgets.

But I've worn it for several days and the numbers it's producing are fantastic. "Fantastic" as in Wow, look how many APs I earned! And, unfortunately, "fantastic" as in Can I really believe the numbers?

For example, last Friday I put on my pedometer upon getting out of bed at 5:30 am. I went to the gym for my workout, ran for 30 minutes and then went about my normal, everyday activity. When I took it off at 5:30 pm, the pedometer informed me I had walked 18,000+ steps for the day, logged more than 8 miles and earned 11 APs (see the picture above).

Now, I'm an active person, but I can't believe I am that active, as nice as it read. (I did pause the pedometer any time I was in the car in case the vibrations were calculated as steps.)

Thinking about it over the weekend, I thought that perhaps the average stride I used (set by the pedometer according to my height) was too long. I lost the manual, so I went online to try to find a manual to figure out how to customize and reset my length. My Googling found no manual, but evidence that others were questioning the pedometer's accuracy as well.

I remembered I owned another pedometer, an Omron HJ-112, so I decided to conduct an experiment.

Today, I wore both pedometers on my right hip from rising (7:30 am) for 12 hours. Each was updated with my height, weight and my custom stride length (21 inches). The Omron doesn't feature a Pause button like the Weight Watchers pedometer, so I didn't use the Pause button today. Anytime I was in the car, before I drove I wrote down the current step numbers on each and then the step numbers when I arrived at my destination, ensuring I could subtract any "false steps" generated by the car vibrations at the end of the day.

I was in the car three separate times over the day and each time the Omron pedometer did not register time in the car as steps. Each time I got to my destination, the number of steps taken on the Omron unit was unchanged from the time I started the trip.

Without employing the Pause button, the WW Points+ Pedometer racked up hundreds of false steps - 459 to be exact. But, I would argue that's why they built in a Pause button. And, I remember it is clearly stated in the manual to hit Pause if you're riding in or driving a car.

So, what were the numbers at the end of the day?

Steps taken: Weight Watchers PointsPlus pedometer: 18,585 (subtract 459 as false steps). Adjusted minus false steps: 18,126.

Steps taken: Omron HJ-112: 10,992.

Miles walked per Weight Watchers PointsPlus Pedometer: 6.15

Miles walked per Omron pedometer: 3.46

No doubt, the Weight Watchers pedometer's senor is super sensitive. And, you could argue, inaccurate in its assessment of steps and miles walked and APs earned.

This post isn't meant to bash Weight Watchers or its products, but serve as a PSA that the numbers on your hip may not be as great as they read. I'm concerned that members using the pedometer would trust the number of APs earned and eat all or some of them, which would perhaps affect their weight loss.

Given I'd rather be conservative in my estimates of APs earned, I'm putting my PointsPlus pedometer in my drawer. I hope Weight Watchers will sometime offer a more accurate pedometer that calculates APs. I will miss that feature.


  1. I'm glad to see your thoughts on the pedometer as I had the same experience. I bought one when the new program came out and also questioned the accuracy of the step count. It measures about 35-40% higher than my old step counter. I guess the whole "if it seems too good to be true..." theory is definitely in action here.

  2. it takes everything into acct, including tapping feet. so if you are fidgety, I suggest making sure it is paused evertime you sit, or go to the bathroom and so on.