This item covers all hours worked or paid for at the establishment, including actual overtime hours (not straight-time equivalent hours). It excludes hours paid for vacations, holidays, or sick leave when the employee was not at the establishment. Excluded are hours worked by employees of contractors and hours of proprietors or partners.

Note: Beginning with the 2006 ASM, for employment and related fields (payroll, production hours, benefits), respondents were asked to report only those full- and part-time employees whose payroll was reported on the IRS Form 941 filing for the Employer Identification Number (EIN) used by that manufacturing establishment. Other temporary workers and workers whose payroll was reported under a different company's EIN were reported elsewhere on the form. In 2002, these data constituted between 1 and 1 1/2% of the total for these fields. Comparisons of data prior to 2006 should be used with caution.