Comparing Zeo, Bodymedia and Sleep Time app scores - surprising findings

Quantified Self Sleep
1

I replicated my zzzsperiment from September, this time measuring sleep concurrently using Zeo, Bodymedia and Sleep Time app (I am currently testing Sleep Cycles) for over a month. I looked at the correlations and compared means/medians, and it seems like:

  1. the summary metrics provided by these devices/apps measure different constructs. essentially, ZQ score and Sleep Efficiency scores are different metrics.
  2. total time slept estimates, however, seem to be comparable and interchangeable
  3. deep+REM sleep time estimates are not comparable
  4. the total time slept has a higher predictive “value” than summary score (i.e., is more useful in predicting some aspects of everyday life).

http://measuredme.com/2012/12/comparing-zeo-bodymedia-and-sleep-time-app-sleep-metrics/

My next step is to explore in more detail predictive power of both ZQ score and Sleep Efficiency scores by Bodymedia and Sleep Time/Sleep Cycles. I was wondering if anyone else has conducted a similar self-experiment and what were your results?