If you’re trying to build a self-driving car or detect whether a picture has a cat in it, big data is amazing. But here’s a secret: If you’re trying to make important decisions about your health, wealth or happiness, big data is not enough.
The problem is this: The things we can measure are never exactly what we care about. Just trying to get a single, easy-to-measure number higher and higher (or lower and lower) doesn’t actually help us make the right choice. For this reason, the key question isn’t “What did I measure?” but “What did I miss?”
To see the dangers of big data untethered to any other kind of analysis, consider the story of Zoë Chance, a marketing professor at Yale. In a TEDx talk that has been watched hundreds of thousands of times on YouTube, she discusses her experience with a pedometer. She became so obsessed with increasing the count of her steps that she lost all proportion, taking walks at all hours and in all places. She told us that she even put the pedometer on her daughter so that her daughter’s steps would contribute to her number. She was able to “detox,” as she put it to us, only after she suffered an injury while walking in the basement, exhausted, in the wee hours of the night.