Inaccurate Scales: A Weighty Problem For The Quantified Executive

A Range of Scales

"I always say you shouldn't weigh yourself. I don't even have a set of scales in my house." - Kim Kardashian

Well, until yesterday, I didn't have a "set of scales" in my house either. But, as you can see, I do now. Wondering why?

A Change in Lifestyle

In my quest to become a healthier, fit person, I have adopted the lifestyle of the healthier, fit person I want to become. For me, technology has been a magical key that has unlocked the secret to that lifestyle. The benefits have been weight loss, extra energy, a sense of well being and – as my daughter Alexis describes it – "charming Shelly," as opposed to the grumpy, cynical, curmudgeonly Shelly from days of old.

The good news is that my "behave like the person you want to be" philosophy does not require me to ever step on a scale. My weight loss (approximately 26 pounds so far) is a result of how I have chosen to live, eat and exercise. I'll stop losing weight when my body reaches the weight it wants to be. However...

The Quantified Executive

I'm a huge geek (well, slightly less huge than I used to be), but a geek nonetheless. And, like I said, the key to my lifestyle change has been technology. Some people call it the "Quantified Self" movement; I'm calling it, "The Quantified Executive." No matter what you call it, here is how it works.

3,500 calories = 1 pound. Eat 3,500 calories more than you burn, you will gain a pound. Eat 3,500 calories less than you burn and you will lose a pound. The math is inviolate.

To make this equation actionable, you need accurate measurement tools. For me, the routine is easy. I enter every single morsel of food I consume into the MyFitnessPal app on my smartphone. This gives me the best approximation of the amount of calories I consume.

I wear a Jawbone UP bracelet and I use two apps with it: the UP app, which measures my approximate calories burned from walking (and which also gives its own version of interesting, but less useful, sleep tracking). And I use RunKeeper to track my daily walks.

Using just these three apps, I've been able to quantify my behaviors – and, much more importantly, adapt my behaviors to my benefit. As a Quantified Executive, I know the power of data – and so do you.

Therein Lies the Rub

Which brings me to my "set of scales" problem. Part of the process of quantification is tracking results. I know that the calorie/weight equation is correct, but there are several variables in my process. Some days I eat bigger lunches or have to eat at a restaurant. The difference between the amounts of oil in two tablespoons of homemade salad dressing vs. restaurant salad dressing can be enormous. If you're trying to limit your caloric intake to 1,500/day, a wrong move or brain fade can cost you close to 10 percent of those calories (yes, in just two tablespoons of dressing).

My progress tracking method of choice has been the Withings WS-50 digital scale. It reports my weight to my smartphone and generates a bunch of less useful data like heart rate, estimated BMI and air quality. Having a digital scale that you can trust is great. I get on the scale every morning (when I'm home) and the app and associated website create a digital record of each event. Over time, a delightful graph is generated which illustrates my progress.

Now, one of the big problems facing the quantified self movement is that very few apps and devices speak the same language. There are no industry standards for measurement or easy ways to see all of your various activities tracked against each other. The answer, for me, and everyone else who is trying to quantify their lives, is Excel. I've created a spreadsheet that takes my caloric intake from MyFitnessPal, my estimated calories burned from UP, and my weight from my Withings WS-50 scale. I use the spreadsheet to track (and project) my progress.

Mixed Results

In order to keep the data on this spreadsheet as meaningful as possible, I need accurate weight measurements daily. I encountered one minor problem – that I spend my weekends in CT and my weekdays in NYC – but that has a simple answer: I purchased an additional Withings scale for CT. In this case, I purchased the WS-30, because the "extra" measurements available on the WS-50 are meaningless.

I was so excited (relatively speaking) by the prospect of weighing myself every day. That excitement didn't last long.

The first time I used the WS-30, the readings were about 1.3 pounds different from the previous day's readings taken by the Withings WS-50 and, sadly, had nothing to do with the old-fashioned digital scale that was already in the bathroom in CT.

To confirm my technology problem, I brought my WS-50 up from NYC so I could do a "three scale" showdown a few seconds apart. The results made me very sad:

  • 224.2 - Withings WS-50
  • 224.9 - Old-fashioned digital scale
  • 225.7 - Withings WS-30

Now it's the end of August, and I'm down somewhere around 26 pounds since the beginning of May, so I can't really complain, but…  a 1.3 pound differential in a world where I'm tracking and projecting .25, .33 and .50 pound per day reductions in weight, with a goal of 2 pounds per week (7,000 more calories burned than consumed), this kind of discrepancy is unacceptable in the extreme!

Is there a solution? Sure: just use one scale that you don't move and only weigh yourself once or twice per week. But, at least in the case of these two Withings scales – accuracy (or being calibrated to display the same weight regardless of actual accuracy) is not possible.

So, Quantified Executives beware – un-calibrated, inaccurate measurement technology, that is not designed to mix and match can be your undoing. (Did I hear someone say Nielsen, Arbitron, Rentrak, Google Analytics, Omniture, ComScore, etc... oops!) It's a weighty problem indeed.