Episode Summary

On today’s episode, we discuss whether there is safety in numbers.

Episode Notes

We use the 2019 paper, Safety in Numbers, to frame this week’s discussion.


  • The amount of exposure increases the amount of risk.
  • Safety in Numbers is a 2019 update to a 2017 paper of the same name.
  • Why you should get down and dirty with the numbers.
  • Be careful about what stats do and don’t tell you.
  • How volume affects risk potential.
  • Rate vs. raw number.
  • How our systems encourage familiarity with risk.


“A lot of statistically dodgy stuff gets published in some very, very good journals and some otherwise very good authors.”

“When something is psuedo-science, you tend to find that there are some studies that say that it works…until the very best studies show that the effect doesn’t work at all.”

“Whenever you use a concept of a rate instead of a raw number, you are assuming a linear relationship.”


Elvik, R., & Goel, R. (2019). Safety-in-numbers: An updated meta-analysis of estimatesAccident Analysis & Prevention129, 136-147.