A corpus analysis by Gkatzia and Mahamood (2015) shows that intrinsic human-based measures are used to a much greater degree compared to extrinsic human-based evaluations, although increasingly more effort regarding the latter evaluation can be observed in the past few years (Gkatzia et al., 2017;Goldstein et al., 2017;Ramos-Soto et al., 2017, for instance) These extrinsic task-focused evaluations have traditionally been regarded as the type of evaluation that provides the most meaningful results.
it can be an expensive and timely undertaking to execute such an evaluation (Reiter and Belz, 2009).