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Pink_Axolotl151 t1_j2s7n6z wrote

Also, keep in mind that the publicized control failure rates represent failure over a 1-year period, but the longer you go out, the higher the failure rate. For example, for male condoms, the failure rate of perfect use is 2% in 1 year, but 18% over a 10-year period. For typical use, it’s 18% after 1 year and a whopping 86% after 10 years. This article has interactive charts that show how the failure rates with perfect and typical use are compounded over time for several different types of birth control:

https://www.nytimes.com/interactive/2014/09/14/sunday-review/unplanned-pregnancies.html

I know that’s not exactly what you asked but I like to throw out this information because I think it’s important.

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derioderio t1_j2sql24 wrote

That's just pretty basic math though:

1-(1-0.2)^10 = 0.18

1-(1-0.18)^10 = 0.86

etc.

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Pink_Axolotl151 t1_j2svyz2 wrote

I’m an immunologist; we don’t do math.

Kidding, kidding, I understand, but I don’t think it’s intuitive to most people that it works like that. A lot of people think that the quoted failure rates (ie, 2% for male condoms) are the failure rates over a lifetime of use, and the graphics in the article help hammer the message home.

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