Effectiveness shows the likelihood of getting pregnant while using a birth control method. Let’s use the Pill as an example. The Pill is 93% effective according to the CDC. That means that 93% of people won’t get pregnant in a year using that method. To put it another way, if 100 people use this method for a year, 93 of them won’t get pregnant.
The medical community talks about efficacy in two ways: perfect-use and typical-use.
Perfect-use effectiveness describes how likely you are to get pregnant if you use a method exactly according to the guidelines. Using the Pill perfectly would mean that you take it at the exact same time every day, never miss doses, or use a backup method while taking certain medications that could make it less effective.
Typical-use effectiveness describes how likely you are to get pregnant if you use a method “typically.” When researchers determine typical-use they study real people actually using the method in their everyday lives over the course of a year and see how many of those people get pregnant. With condoms for example, that group would include people who don’t always use condoms when they have sex or don’t put them on or take them off correctly.
It’s hard to be perfect. That’s why on our birth control materials we use typical-use efficacy whenever possible. If your preferred method has a lower typical-use efficacy rate than you are comfortable with, talk to your medical provider about ways to make it more effective. Your provider might suggest setting reminders on your phone, show you how to put condoms on and take them off correctly, or resources to use with Fertility Awareness Methods such as apps or charts.