Episode Summary

On this episode of Safety of Work, we wonder if there are more accidents on Friday the 13th.

Episode Notes

To frame our discussion, we decided to reference a few papers. The papers we use are Females Do Not Have More Road Accidents on Friday the 13th, Much Ado About the Full Moon, and Moon Phases and Nighttime Road Crashes Involving Pedestrians. Tune in to hear our chat!


  • Calendar effects.
  • Gendered calendar effects.
  • The full moon effect.
  • Contradictory studies.
  • Superstitious safety practitioners.


“The idea is that if it’s a robust result, it should apply regardless of the decisions you make…”

“It’s becoming increasingly common now for researchers to publish their raw data alongside their publications, so that other authors can actually make their own assessment of the papers…”

“We’re pretty sure that accident-proneness is really a symptom of confirmation bias or statistical artifacts.”


Näyhä, S. (2002). Traffic deaths and superstition on Friday the 13thAmerican Journal of Psychiatry159(12), 2110-2111.

Radun, I., & Summala, H. (2004). Females do not have more injury road accidents on Friday the 13thBMC public health4(1), 54.

Redelmeier, D. A., & Shafir, E. (2017). The full moon and motorcycle related mortality: population based double control studybmj359.

Rotton, J., & Kelly, I. W. (1985). Much ado about the full moon: A meta-analysis of lunar-lunacy researchPsychological bulletin97(2), 286.