Statistics are becoming more important as court cases address increasingly complex problems. Sometimes the statistician analyzes data that can help the judge or jury decide whether someone is guilty of a crime or must pay damages for causing injuries.
A prosecutor who is offering hair fibers found at the scene of a crime as evidence may want to introduce testimony that a match with the defendant's hair would be more than coincidental.
A person claiming a business discriminates on the basis of race or sex when paying its employees may introduce a statistical study of the factors related to salaries.
In trademark cases, when one company uses another's trademark or something very similar to it, surveys of consumers may be done to see whether they recognize the brand name or are confused or misled by the competitor's advertising.
Medical statistics are crucial in judging whether a drug or medical device has toxic effects and was the probable cause of a disease contracted by the plaintiff.
Once negligence has been established, the amount of money the negligent party must pay may be based on statistical predictions. What would an employee have earned had there been no illegal discrimination? What would a company's sales have been had there been no unfair competition?
As these examples indicate, attorneys need to retain statisticians (and other professionals with statistical expertise) who may be consulted or asked to testify on a wide range of subjects. Such statisticians must know not only how to handle statistics, but also how to present their work effectively to lawyers, judges, and jurors who are not skilled in mathematics.
Forensic statistics is an especially challenging branch of applied statistics that draws on all kinds of statistical analyses and many areas of expertise.