The problem with the 'quantified self' is that more information doesn't necessarily lead to better outcomes. Even in cases where the stakes are high and information seems essential, like pregnancy and childbirth, more monitoring isn't better. That's true of 'routine' ultrasound monitoring during pregnancy (http://www.nejm.org/doi/full/10.1056/NEJM199309163291201) as well as heartbeat monitoring during birth (http://evidencebasedbirth.com/evidence-based-fetal-monitorin...).

What does work is identifying cases where there is genuine cause for concern - symptoms for healthcare patients, lack of ability to complete tasks for procrastinators - and collecting the data needed to determine if/when intervention is required.

The challenge for the quantified-selfers will be to sort the signal from the noise.