Explanation: Not all birth control works equally well. All methods have a chance of failure. When used correctly each time, the failure rates are lower. In general, barrier methods -- such as diaphragms, cervical caps, and male condoms -- are about 84% effective (although condoms are 98% effective when used correctly). Hormonal birth control such as the pill, vaginal rings, and patches are 99% effective with perfect use. Implants, IUDs, and shots are about 99% effective.