4 ms·

The website right now calls the app 99% effective when used as directed. Ars is typically high quality, so I'm going to assume this isn't a Pharma hit piece. Th

The website right now calls the app 99% effective when used as directed. Ars is typically high quality, so I'm going to assume this isn't a Pharma hit piece. That FDA approval must be based off better looking data than the 1990 study, right? I hope?

0xcde4c3db 8y ago
If the only inputs are daily oral temperature and menstruation dates, I have a hard time believing that they get to 99% without essentially fudging the number via a convenient definition. For example, total ratio of users who do/don't get pregnant over a given time period regardless of how frequently the user is having sex or what other contraceptive methods they might be using.
- bena 8y ago
  I think the fudge here is "as directed". As in if you put in all of the data accurately, take it accurately, and don't accidentally mess it up in one of the 700 simple ways to do so, it is 99% effective.
giarc 8y ago
It also states that it is 93% effective when used typically. Clinical studies have shown that Natural Cycles is 93% effective.* * Even with using the app perfectly, you can still have an unintended pregnancy. Natural Cycles is 93% effective under typical use, which means that 7 women out of 100 get pregnant during one year of use. With using the app perfectly, i.e. if you never have unprotected intercourse on red days, Natural Cycles is 99% effective, which means 1 woman out of 100 get pregnant during one year of use
SmellyGeekBoy 8y ago
I've been with my wife for over 18 year years now. In a good year we probably have sex 100 times. If we'd been using this app for that time and ended up with 18 pregnancies in that time I'm not sure we'd agree that this is an effective method of contraception!
- neaden 8y ago
  That's not how failure rates for birth control are calculated. The percentage is for a pregnancy occurring during a year with that method.
yummybear 8y ago
An interesting comparison to condoms: "If you use condoms perfectly every single time you have sex, they’re 98% effective at preventing pregnancy. But people aren’t perfect, so in real life condoms are about 85% effective — that means about 15 out of 100 people who use condoms as their only birth control method will get pregnant each year."

0xcde4c3db 8y ago

If the only inputs are daily oral temperature and menstruation dates, I have a hard time believing that they get to 99% without essentially fudging the number via a convenient definition. For example, total ratio of users who do/don't get pregnant over a given time period regardless of how frequently the user is having sex or what other contraceptive methods they might be using.

bena 8y ago
I think the fudge here is "as directed". As in if you put in all of the data accurately, take it accurately, and don't accidentally mess it up in one of the 700 simple ways to do so, it is 99% effective.

giarc 8y ago

It also states that it is 93% effective when used typically. Clinical studies have shown that Natural Cycles is 93% effective.* * Even with using the app perfectly, you can still have an unintended pregnancy. Natural Cycles is 93% effective under typical use, which means that 7 women out of 100 get pregnant during one year of use. With using the app perfectly, i.e. if you never have unprotected intercourse on red days, Natural Cycles is 99% effective, which means 1 woman out of 100 get pregnant during one year of use

SmellyGeekBoy 8y ago

I've been with my wife for over 18 year years now. In a good year we probably have sex 100 times. If we'd been using this app for that time and ended up with 18 pregnancies in that time I'm not sure we'd agree that this is an effective method of contraception!

neaden 8y ago
That's not how failure rates for birth control are calculated. The percentage is for a pregnancy occurring during a year with that method.

yummybear 8y ago

An interesting comparison to condoms: "If you use condoms perfectly every single time you have sex, they’re 98% effective at preventing pregnancy. But people aren’t perfect, so in real life condoms are about 85% effective — that means about 15 out of 100 people who use condoms as their only birth control method will get pregnant each year."