Based in Rotterdam, The Netherlands, Tapijt Express, B.V. is a small carpet cleaning business founded by a former advertising manager. The company cleans carpets for both commercial and residential clients. The company was founded about five years ago, and has since grown substantially, averaging about 30 new clients and two new employees a year. The company currently employs eight seasonal employees who are responsible for a certain number of hotel clients. Each morning crews are assigned to jobs by the owner. Crew sizes range from two to four workers. Crew size and composition are a function of the size of the building and the requirements of the job. The owner feels that large, commercial jobs should be assigned to crews of four workers in order to complete the job in reasonable time. From time to time, the owner noticed that some jobs, especially the largest ones, took longer than she had estimated, based on the size of the floor space involved. The owner’s son, Geert, decided to investigate. He kept records of job times and crew sizes, and then used those records to compute labour productivity. The results were: Since the company operates on a small profit margin, it is especially important to take worker productivity into account.
Question.
Which crew size had the highest productivity? Which crew size had the lowest productivity? What are some possible explanations for these results?