This enumerated value indicates whether the current-day Section-layer statistics bucket has accumulated valid data yet, reading notValid if the day's collection period hasn't been running long enough. An admin cares because trusting the day's cumulative ES/SES/SEFS/CV counts for threshold comparisons requires this flag to read valid first; checking it right after a device reboot would show notValid. For example, a device that rebooted six hours into the day would show notValid here for a portion of that day until enough of the collection window has elapsed to be considered valid.