Are APA journal articles getting longer or shorter over time? Earlier work that examined changes over time in article length in 24 APA journals (1986-2005) found that pages per article increased over time for the average journal, peaking around 2001, and then plateaued thereafter. But have these trends continued during the past 14 years? The current research extends prior work by adding additional years (1986-2019) and four additional journals (28 journals, 34 years, and 865 total observations). Multilevel growth curve analyses revealed a cubic effect of time on average article length, showing an increase in the 1980s and 1990s, a plateau or slight decline in the 2000s, and a slight increase again in the 2010s. Journal impact factors (JIFs) moderated linear growth over time; journals with higher JIFs had larger linear increases in article length. Exploratory multilevel interrupted time-series analyses suggested that the average linear increase in pages per article over time was greater after the start of psychology's credibility crisis (2012-2019) than before it (1986-2011), which may relate to an increased emphasis on reporting details and transparency. We discuss implications for article length in the contexts of publishing and psychology's ongoing credibility crisis.
Keywords: APA journals; article length; credibility crisis; growth curve modeling; impact factor; multilevel models; publication trends.