The analysis of these data is subject to significant analytical error. (educationnext.org)
Sure, sometimes it just boils down to tough luck, but usually it's due to simple analytical error and / or the consequences of fear & greed. (wexboy.wordpress.com)
It follows that value investors seek a margin of safety, allowing room for imprecision, bad luck, or analytical error in order to avoid sizable losses over time. (novelinvestor.com)