Well, thanks to the Securities and Exchange Commission we now have something close to conclusive proof.
Our conflicts are similar to managing deadly outbreaks of disease, with clear, conclusive victories seldom known or celebrated.
Finding that conclusive link, however, seems unlikely given the track record of these studies.
1610s, "occurring at the end," from French conclusif, from Late Latin conclusivus, from conclus-, past participle stem of concludere (see conclude). Meaning "definitive, decisive, convincing" (putting an end to debate) is from 1640s. Related: Conclusiveness.