The determination of the number of businesses operating in Arizona is not a straightforward proposition due to data deficiencies and definitional issues. The best data — from the U.S. Census Bureau — are more than two years old. The Census Bureau data are divided into two series: businesses with employees and nonemployer businesses. Each series is based on administrative records. While neither series is affected by sampling error, both are subject to nonsampling error. Certain industries are excluded from each series.