Sixty years of quantitative communication research summarized: lessons from 149 meta-analyses RainsStephen A. LevineTimothy R. WeberRene 2018 <p>In an effort to better understand the state of knowledge production in the field of Communication, we examine the results of 149 meta-analyses exploring human communication phenomena. The meta-analyses summarize more than 60 years of quantitative research involving more than 8 million participants. The mean effect estimate is <i>r </i>= .21, and three-quarters of the meta-analyses reported an estimate of less than <i>r = </i>.29. Several trends in the findings from the meta-analyses are examined. The results underscore the notion that communication is a complex and highly contingent phenomenon and highlight some specific instances in which communication variables and processes produce (in)substantial effects. Taken as a whole, this project offers insights about the status of quantitative communication research and the collective efforts of scholars working in our discipline.</p>