Objective We aimed to determine trends over time in article origin, and article and methodology characteristics.

Method We examined original research articles published every fifth year over a 20-year period (1997–2017) in six emergency medicine (EM) journals (Ann Emerg Med, Acad Emerg Med, Eur J Emerg Med, Emerg Med J, Am J Emerg Med, Emerg Med Australas). Explicit data extraction of 21 article characteristics was undertaken. These included regional contributions, specific article items and research methodology.

Results 2152 articles were included. Over the study period, the proportional contributions from the USA and the UK steadily fell while those from Australasia, Europe and ‘other’ countries increased (p<0.001). All specific article items increased (p<0.01). Institutional Review Board/Ethics Committee approval and conflicts of interest were almost universal by 2017. There were substantial increases in the reporting of keywords and authorship contributions. The median (IQR) number of authors increased from 4 (2) in 1997 to 6 (3) in 2017 (p<0.001) and the proportion of female first authors increased from 24.3% to 34.2% (p<0.01). Multicentre and international collaborations, consecutive sampling, sample size calculations, inferential biostatistics and the reporting of CIs and p values all increased (p<0.001). There were decreases in the use of convenience sampling and blinding (p<0.001). The median (IQR) study sample size increased from 148 (470) to 349 (2225) (p<0.001).

Conclusion Trends over time are apparent within the EM research literature. The dominance in contributions from the US and UK is being challenged. There is more reporting of research accountability and greater rigour in both research methodology and results presentation.