If the results of one study are replicated with additional studies, what does this imply about the initial study?

When the results of an initial study are replicated successfully in additional studies, this indicates reliability. Reliability refers to the consistency of a measure; that is, if the same study is conducted under similar conditions, it should yield similar results. Replication demonstrates that the findings are not just a one-time occurrence or due to random chance, suggesting that the study's methodology can produce the same outcomes consistently.

In contrast, validity refers to whether the study truly measures what it claims to measure. While replication can support aspects of validity, it is primarily the consistency across multiple studies that supports reliability. Usability focuses on how easily the findings can be applied in practical situations, which is an important aspect but not directly related to replication. Feasibility concerns whether the study can be conducted under real-world conditions, which is not necessarily demonstrated through replication and instead pertains to the practicality of the study design. Thus, reliability is the most appropriate implication of successful replication of study results.