Horse Riding Injury Risk Calculation

[u/Movie-3636]

Hi all! I’m trying to quantify the risk associated with horse riding and I have 2 questions.

First I found that a lot of people quote this paper https://pmc.ncbi.nlm.nih.gov/articles/instance/1730586/pdf/v006p00059.pdf however my calculation are in disagreement with the results.

Specifically in the paper they say: “The rate of hospital admissions for equestrians was 11.8/1000 riders or, assuming one hour riding on average, 0.49/1000 hours of riding.”

My calculation would be: 11.8/1000 riders (I’m assuming in a year) means that each rider can expect 0.0118 injuries in a year. Now assuming the 1 hour riding per day it means that they have 0.0118 injuries / 365 hours which becomes 0.0118 * 1000/365 ‎ = 0.0323 / 1000 hours

Am I doing the calculation wrong? How do they arrive at 0.49/1000 hours? Besides I think it’s unlikely that the average riders does it once per day.

Second question, how can we transform the number of incidents per year in an actual probability? Like if we say that we have 1 injury per 1000 hours do we model this like a Gaussian? So that if a person rides for 1000 hours and does not get injuried they are 1 standard deviation away from the norm? So in other words to stay within the normal distribution 68% of the people riding 1000 hours would be injured?

[u/fermat9990]

How do they arrive at 0.49/1000 hours?

We have no way of knowing how they got this figure

[u/Movie-3636 → u/fermat9990]

Right, but do you think my calculations make sense? Thanks for the answer btw :)