Appendix: Answers to Lesson Questions

Lesson 1

  1. 150 calls.
  2. 2 minutes.
  3. 50 calls.
  4. 25 minutes.
  5. Cycle time dropped from over 11 hours to under 40 minutes.
  6. Level2 utilization dropped to 51.81%.
  7. That is bad because they are only busy half of the time they are available to work.
  8. Perform Research.
  9. The queue is no longer used
  10. The average quantity in the queue is 3.71
  11. The average time in queue is 78.81 minutes
  12. Level 1 = 53.38%, Level 2 = 89.70%.
  13. The utilization of both resources is about 70%.
  14. Low cost, fast turn-around, no disruption to live system, try solutions that would be impractical to test on a live system.

Lesson 2

  1. Level 2 resource utilization of 92.36 and standard deviation of 4.32.
  2. Cycle time of 316.11 and standard deviation of 244.73.
  3. The 25% and 75% routings.
  4. How long does it usually take to perform this operation? What is the longest it has ever taken? What is the shortest amount of time it has ever taken?

Lesson 3

  1. 80.21
  2. 34.04
  3. On average less calls arrive per hour in lesson three (12 vs 15). Entities only come in between 8 am and 4 pm, but resources can continue to work after 4 pm to handle any backlog.
  4. 1.67
  5. Click Simulation / Options and set the run length to 168 hours or 7 days.
  6. This is a tricky question. Changing any element in the model will alter the random pattern. You would need to run replications of the original and the changed model to predict the outcome accurately. The model with one large pattern has a greater potential for variation, so more entities could bunch together during arrivals and cause longer waiting times.

Lesson 5

  1. Yes.
  2. Total cost, cost per call, unused resource cost, the total number of calls returned, and customer satisfaction.
  3. Despite higher costs, adding a second resource is likely a better choice than staying with 1 resource. Throughput is much better, customers will be happier with shorter wait times, and your employees will probably have higher job satisfaction since stress levels will be significantly lower. The cost of customer dissatisfaction is hard to measure, but generally, you should strive for the best service possible. Employee burnout is likely to be much higher in the case of only one Level 2 resource. That can end up costing a great deal in many different ways.
  4. Yes, as noted in earlier lessons. It is important to remember that the simulations must be run and the results compared before assuming one solution is better. You might be surprised at the results of some of the experiments.
  5. If Name = Item Then a_Route = D2(40,2,60,3).
  6. Create a variable (e.g., v_ReworkCount) with an initial value of 0. On the rework route (returning to Production), add the action logic “Inc v_ReworkCount). In the output report, scroll to the bottom section to view the variable’s stats.

Lesson 6

  1. No, the system falls behind
  2. Add a second resource in the Level 2 position. Change the lunch breaks for Level 1 and Level 2, so they don’t overlap. Make the Level 2 resource an alternate to Level 1 for answering calls, so when Level 1 is at lunch, Level 2 will answer calls.

Lesson 7

  1. 10
  2. Some returned calls are not resolved satisfactorily. So they have to do more research and return the call later.
  3. 2
  4. 3
  5. TSR2 is helping TSR1.
  6. Since the route is not connected to any other activity, they exit the system.
  7. Run multiple replications, then view the average values in the output report rather than each individual replications’ result.

Self Teaching Guide

Getting Started


  1. Your First Model
  2. Replications and Distributions
  3. Entity Arrivals
  4. Routings
  5. Attributes, Variables and Action Logic
  6. Shifts
  7. A More Complex Call Center
  8. Model Building Techniques

Case Studies

  1. Analysis
  2. Replications
  3. Froedtert Hospital Improves ICU Care
  4. Nuclear Site Cleanup
  5. Restaurant Customer Seating Optimization

Appendix: Answers to Lesson Questions

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