This enumerated value indicates whether the current 15-minute Section-layer statistics bucket contains valid accumulated data yet, or is still notValid because the interval hasn't completed or just started. An admin cares because pulling cwSonetSectionCurrentESs/SESs/CVs counters while this flag reads notValid means those numbers are incomplete and shouldn't be compared against a full-interval threshold. For example, checking these counters immediately after an interface reset would show notValid here, warning the admin the section error counts collected so far are only a partial sample.