Investors will be startled to see just how well developed Putrino's notion is of the deep limits lurking in the dozens of consumer-grade body motion and data capture devices bulking up today's hip "quantified self" movement. First off, manufacturers tend to be mum about exactly what their devices can and can't do. A very nice Leap Motion spokeswoman, Chelsea Guidice, declined to comment for this story. As did Joseph Teegardin, a press contact at Nike ( NKE - Get Report) and several representatives at the Kinect group at Microsoft. With some digging, it's possible to get a feel for the body of work on the pitfalls of consumer-grade motion sensing tools. Microsoft, to its credit, produces a sophisticated, open and free online Human Interface Guidelines kit for Kinect developers where it is made clear that the Kinect creates only the raw data. It's up to the application developer to interpret that information properly and create a functioning app. "Kinect for Windows enables a lot of new interaction, but also new challenges," the guide warns. "It's especially hard to guess ahead of time what will work and what won't. Conduct user tests often and early." The sense of small developers scaling a giant mountain of motion control data is confirmed in Leap Motion's similar open developer space. Apart from the sheer overwhelming amount of information developers better know their way around, there's a recurring "work in progress" vibe. "Not really sure what to do next," said one post in the Leap Motion online resource. "But I'm sure there's some cool stuff you could do with a system like this." And then there is the Nike+. FuelBand. Teegardin confirmed that the FuelBand is a closed commercial development platform for which only carefully screened partners are given access to core technology. For example, there is the Fuel Lab, where developers race to create apps for a $50,000-per-team prize. But deep in Nike's online FuelBand literature is a manual that discloses that the tool is nothing more than a Class B FCC digital device -- one that Putrino said need not have its claimed health benefits confirmed with regulators such as the Food and Drug Administration.
As Putrino explained it, at the heart of the issues with quantifying the self is how the captured data is ultimately interpreted. The bits of mathematics involved are known as "inverse kinematic algorithms," algos that have exploded in popularity as the video game revolution unfolded. Putrino pointed me to dozens of them littering many game-developer forums, as well as the utter lack of resources needed to confirm they are accurate. "The question you have to continually ask here is, 'How did you validate what you are seeing?'" Putrino said. "Developers mean well. But there's a culture of kids grabbing an algo and running with it. That approach simply does not stand up to rigorous analysis." And the damage can be real. Putrino worries deeply than a new generation of general-purpose consumer motion-capture devices are making claims that are impossible to confirm, much less challenge. "The truly dangerous devices are the ones that say no matter what shape, size or fitness level you are, if you use our one-size-fits-all device we'll tell you how many calories you are burning, how far you ran and how much work each of your muscles did -- and therefore what your next choice of action should be,' he said. "These devices are nothing more than the 'qualified self,'" he said. "It's simply nonsense."