After seeing around 25% less distance recorded by my fitbit as measured by a garmin measured trip, it was getting fustrating. My fix was to carry a water bottle in the same hand that that has the fitbit strapped to it. With my arm never dangling, the measurement is almost spot on. I think with my arm hanging down it throws the accelerometer off. Anyway, it works for me and I'm happy getting the correct readings. Love this little gadget.
