Here's how 2% per incident is different:

Let's say, hypothetically speaking, that the average number of uses per year is 100.

A 2% per incident risk will add up to a yearly 50% risk for the average user.*

A 2% per year risk already included 100 uses, so it is still 2% per year.

A 2% per year risk would add up to a 70% chance over the 35 or so years women are fertile and active and a 2% per incident risk would add up to a much, much higher risk, likely resulting in multiple pregnancies.*

* This is only if pure math reflects reality, which it probably doesn't because there are other factors here like people forgetting important parts of the instructions over time, people getting better at using them over time, or people becoming sloppy about applying them because they're tired of them or have developed a sense of over-confidence.

This is only if pure math reflects reality,

No, it requires that the failures of condom usage be independent events from one another. That is to say, that person A using a condom at time B has the same probability of failure as person C using a condom at time D, even if C=A or B=D.

Without knowing more, it is entirely possible that some fraction of men have supersperm which gets through condoms and that they account for all the failures, and those that use condoms but avoid supersperm will never fail. Alternatively it is possible that some group of pe... (read more)

0[anonymous]7yI think the figure you're looking for is 1 - (0.98^100) = 0.87 (assuming no-one gets pregnant twice in the same year).

Public Service Announcement Collection

by Eliezer Yudkowsky 1 min read27th Jun 2013330 comments


P/S/A:  There are single sentences which can create life-changing amounts of difference.

  • P/S/A:  If you're not sure whether or not you've ever had an orgasm, it means you haven't had one, a condition known as primary anorgasmia which is 90% treatable by cognitive-behavioral therapy.
  • P/S/A:  The people telling you to expect above-trend inflation when the Federal Reserve started printing money a few years back, disagreed with the market forecasts, disagreed with standard economics, turned out to be actually wrong in reality, and were wrong for reasonably fundamental reasons so don't buy gold when they tell you to.
  • P/S/A:  There are many many more submissive/masochistic men in the world than there are dominant/sadistic women, so if you are a woman who feels a strong temptation to command men and inflict pain on them, and you want a large harem of men serving your every need, it will suffice to state this fact anywhere on the Internet and you will have fifty applications by the next morning.
  • P/S/A:  Most of the personal-finance-advice industry is parasitic and/or self-deluded, and it's generally agreed on by economic theory and experimental measurement that an index fund will deliver the best returns you can get without huge amounts of effort.
  • P/S/A:  If you are smart and underemployed, you can very quickly check to see if you are a natural computer programmer by pulling up a page of Python source code and seeing whether it looks like it makes natural sense, and if this is the case you can teach yourself to program very quickly and get a much higher-paying job even without formal credentials.