Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Pearl Index
open-in-new
<p>The Pearl Index, also called the Pearl rate, is the most common technique used in <a href="/facts/Clinical_trials/q8LMr832">clinical trials</a> for reporting the effectiveness of a <a href="/facts/Birth_control/qCzhxgH8">birth control</a> method. It is a very approximate measure of the number of unintended pregnancies in 100 woman-years of exposure that is simple to calculate, but has a number of methodological deficiencies. </p><p>The index was introduced by <a href="/facts/Raymond_Pearl/PCuN2uBU">Raymond Pearl</a> in 1934. It has remained popular for over eighty years, in large part because of the simplicity of the calculation. </p>