By FTE's. (Full time equivalents) They take the history of their business and project or anticipate the expected business. Then they measure their full time employees (note two part timers = 1 FTE) based on the projected volume of business. This may indicate a need to hire or leave as is. In some rare cases where business declines, layoffs may be necessary. (I am in the travel business and we always take our call volume numbers for each week/month from history -same week/month last year; and then determine number of people allowed on vacation and/or if we anticipate allowing people unpaid time off if volume is slow.) Hope that helps a little.

__________________
Best of Yahoo! Answers