In probability and statistics, the base rate (also known as prior probabilities) is the class of probabilities unconditional on “featural evidence” (likelihoods).
It is the proportion of individuals in a population who have a certain characteristic or trait. For example, if 1% of the population were medical professionals, and remaining 99% were not medical professionals, then the base rate of medical professionals is 1%. The method for integrating base rates and featural evidence is given by Bayes’ rule.
In the sciences, including medicine, the base rate is critical for comparison. In medicine a treatment’s effectiveness is clear when the base rate is available. For example, if the control group, using no treatment at all, had their own base rate of 1/20 recoveries within 1 day and a treatment had a 1/100 base rate of recovery within 1 day, we see that the treatment actively decreases the recovery.
The base rate is an important concept in statistical inference, particularly in Bayesian statistics. In Bayesian analysis, the base rate is combined with the observed data to update our belief about the probability of the characteristic or trait
…
Source: Wikipedia
No Comments yet!