While replication of research is the ultimate arbitrator of reproducibility, the process is a bit more complex than it appears. And, like any empirical study, a replication can itself be wrong. However, replications are the best tool available for determining reproducibility if (a) they employ sufficient statistical power; (b) they follow the original study procedures as closely as possible (sans any questionable research practices present therein); (c) their investigators are able to obtain the necessary information, advice, and materials from the original authors; and (d) the replication protocol is preregistered. The chapter describes different types of replications, such as exact (seldom possible for experimental research), direct (the recommended approach, which involves employing the same methodological procedures, outcome variables, and statistical approaches as the original study), conceptual (not recommended since they customarily presume the original results to be correct and are conducted to determine the extent to which said results can be extended), self (primarily useful for the original investigators to convince themselves of the validity of a finding via a replication of an original study to ensure that its results are reproducible), and partial (seldom necessary but useful when there is no alternative, such as when all of the procedures cannot be duplicated for ethical reasons).
Distinguishing Specific from General Effects in Cognition Research