“…Present problems in the field include: (1) insufficient use of double-blind designs (see above, for example only 25 out of the 60 published studies on tDCS effects on motor learning in healthy adults reviewed here utilized double-blind designs) and positive controls (stimulation of other cortical regions); (2) insufficient differentiation and understanding of design and claims when carrying out exploratory (hypothesis-generating) versus confirmatory (hypothesis-driven) research (the former suggesting trends and providing data for prospective power analysis and the latter, strengthened by preregistration (Finkel, Eastwick, & Reis, 2015), allowing drawing conclusions on particular effects; (3) insufficient efforts to reduce false-positive rates in studies geared to provide proof of principle data to power subsequent clinical trials; (4) scarcity of preregistration of hypothesis, design, power analysis and data processing for research written up as hypothesis-driven and confirmatory (see for example https://blogs.royalsociety.org/publishing/registered-reports/); (5) insufficient prepublication and sharing of materials (Lauer, Krumholz, & Topol, 2015;Morey et al, 2016), particularly in relation to negative results; (6) insufficient post-publication repositories of data (see for example (Campbell et al, 2002)) and in general (Nosek et al, 2015)) to allow additional analyses; (7) seldom use of experimental designs with replications built in (Anderson et al, 2016;Cohen et al, 1997;Gilbert, King, Pettigrew, & Wilson, 2016;Nosek et al, 2015); and (8) use of appropriate sample size based on prospective power analysis for studies claimed to be hypothesis-driven.…”