Revisiting Inaccuracies of Time Series Averaging under Dynamic Time Warping.

•Dispels misconception on correctness and drift-out phenomenon of time series averaging.•Shows that correctness-criterion is unsatisfiable and drift-out is inconclusive.•Shows that Fréchet means never drift out.•Suggests coherence of approximations as a special version of drift-outs.•Shows that state-of-the-art averaging methods are incoherent.