Seven deaths due to walking between moving subway cars

MTA is running the following notice in the NY subway trains:

 

The person who wrote the line “7 people died while walking between moving subway cars” wants subway riders to think 7 is a lot, is too many. How we feel about this number depends on what we choose to compare it to. Seven out of 1.7 billion (MTA statistics) seems like a very small risk but if it’s 7 out of 100, it is very dangerous indeed.

The implied denominator can be the number of riders per year or the number of riders who attempt to walk between moving trains per year. Because of the availability heuristic (Kahneman & Tversky), most of us have a stronger sense of the first number than the second. But using the total riders as denominator causes us to vastly underestimate the risk. If the message had said “7 out of 100 people who walked between cars died”, that’s a strong deterrent against walking between cars.

Comments

[Pablo]

The MTA wants to demonstrate that it is "safety-oriented," and marketing gives space on a poster. Is this the leading cause of controllable deaths by some ranking? Is this poster part of a campaign of the leading causes?

Or is this like "don't put makeup on while driving" but never saying "don't text and drive."

[Kaiser]

Pablo: Another way to phrase what you are saying is that the risk should be relative to other causes of death.

[Ken]

In some cases the denominator is irrelevant and probably unknown. These are things that are considered risky and unnecessary that people shouldn't do.