Accurate Results

I finally have some results that are accurate. I don't want to hold my breathe, but these results are right on the money.

What I did:
I ran a mile on the treadmill at a consistent pace. It over calculated my run by .24, so I used that as my guide and calibrated the numbers based on that....I then went on a 3 mile run at a constant speed (6.5) and after my run, I cross referenced the numbers on the treadmill and the sportband. They matched.

I'm wondering if running outside will make a difference? Also, running at various speeds? Also different elevations? And so it goes....To be continued....