Identity theft involves "stealing" another person's personal identifying information, such as their Social Security number (SSN), date of birth, or mother's maiden name, and using that information to fraudulently establish credit, run up debt, or take over existing financial accounts. Precise, statistical measurement of identity theft trends is difficult for several reasons. Federal law enforcement agencies lack information systems to track identity theft cases. Also, identity theft is almost always a component of one or more white-collar or financial crimes, such as bank fraud, credit card or access device fraud, or the use of counterfeit financial instruments. Data sources, such as consumer complaints and hotline allegations, can be used as proxies for gauging the prevalence of identity theft. Law enforcement investigations and prosecutions of bank and credit card fraud also provide data. GAO found no comprehensive estimates of the cost of identity theft to the financial services industry. Some data on identity theft-related losses indicated increasing costs. Other data, such as staffing of the fraud departments of banks and consumer reporting agencies, presented a mixed or incomplete picture. Identity theft can cause victims severe emotional and economic harm, including bounced checks, loan denials, and debt collection harassment. The federal criminal justice system incurs costs associated with investigations, prosecutions, incarceration, and community supervision.