Answer: Reasons given in the text include the following: (1) The most frequently used measure of work is time. (2) Most workers are paid according to the amount of time they work. (3) Workers must arrive at work on time. (4) While on the job, workers must utilize their time effectively. (5) When production workers are paid on an incentive plan, they earn their bonuses based on how much time they can save relative to the standard time for a given task. (6) Labor and staffing requirements are based on workloads measured in units of time.