Most taxpayers are law-abiding citizens who timely file and pay their taxes.
There is another category, non-taxpayers, who either neglect or refuse to pay their taxes. Determining the appropriate method to resolve a delinquent taxpayer's account is based on an analysis of financial statement information. The IRS examines each taxpayer's assets, liabilities, income, and expenses to determine the ability to pay, in the shortest possible time frame. Prior to implementation of national standard expenses, revenue officers determined the allowable amounts of the necessary living expenses. This lent itself to discrepancies, perhaps even within the same group.