Carat determines whether an app is a hog by comparing battery drain when an app is running compared to when it is not running. However, because Carat can only take samples when it is running, it will never have Carat-free data to compare against. That's why it never shows up as a hog.
In other words, Carat knows nothing of a world without Carat; it's a limitation of the approach, but not one that seems to be hindering us.
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