After a 10km walk when my Health app said I did only 6789 steps I then proceeded to walk more that week just so I could up my daily average. Yeah, it sucks for doctors who were hoping to tap into this data but let’s be honest here. Most of the time we rely on self-reported data – did you go for a walk today? Yes of course I did (not). Even if it were accurate what’s to stop someone giving their iPhone to their more active friend for an hour. I can see it now – people jogging down the road with iPhones, FitBits and various strapped to themselves, cards in newsagents offering their activity to others. If we don’t trust humans (and when it comes to health it’s usually best to be at least a little skeptical) why should we trust technology? Surely it is better to have inaccurate data than to have data that actively lies? That day I walked around 12500 steps (according to Google). I knew it (kind of) but my phone didn’t. But how could I blame it? I couldn’t, no… Instead I had to prove it wrong. I was placed in a position where I wanted to also be more truthful to myself – I am inactive (the downside of a PhD) and the one time I did a 10km walk it was important enough that the data rewarded me that I changed my behaviour. Brilliant! Let’s keep measuring steps wrong, let’s keep challenging our technology, because the day that it’s more accurate than we are is the day we stop trying to best it.