When Will You Need This?

Most shifts are decided based on employee preference, rather than customer needs. This tutorial shows you how to uncover the actual resource staffing needs to determine better resource schedules. You will see the quantity of a resource or resources required during each period of the day.

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Resource Usage Calculator

Model Object

The Model Object “Resource Usage Calculator” calculates the resource usage over time and resides in the Resources category of model objects. ‘Insert’ the Model Object into your model and follow the instructions below.

  1. Open the ‘Attributes, Variables & Scenarios’ window (Insert \ Attributes, Variables & Scenarios) and goto the ‘Scenario Parameters’ tab.
    1. Define the value for ‘s_LengthOfAveragingPeriod’ or leave at default. The Averaging Period defines the minutes between recording the number of resources needed (usually 30, 60 or 120 minutes).
      Attributes-window
    2. Define the value for ‘s_SecondsBetweenSamples’ or leave at default. Provides a method to change the frequency of the samples. A smaller number means that samples will be taken more often but will slow the simulation.
    3. Define the values for ‘s_ResName1-5’. Enter the name of the resource you want to track in the default value field. All s_ResName1-5  should have a valid resource name declared, if you do not have five valid resources, you can change the names of the rest to any of the valid resources in your model.
      Attributes Window Resources Renamed
    4. Define the values for ‘s_ResMaxQty1’. Enter the maximum quantity of resources needed at any time during the day. Estimate high if you are unsure.
      1. Copy the scenario parameter (s_ResMaxQty#) to the Quantity field of the resource.
        Resource Quantity
      2. Copy the scenario parameter (s_ResMaxQty#) to the Capacity field of the Activity using the resource. Add the scenario parameter to each activity that uses the resources.
        Activity Quantity
  2. Simulate your model.

Resource-Usage-Calculator

 

Outputs Available

The following steps will help you reach the resource usage results.

  1. Open the Output Report (View \ Output Report) Output Report Icon.
  2. Click the second Excel icon to export variable data and then click ‘Save.’ Export Variable Button Highlighted
    1. Do not rename the report.
    2. Save the report in the same folder as the model.
  3. Choose all the variables ‘v_AveResInUse#’ based on the resources you want to review usage of (the values align to s_ResName#) and click ‘Export.’
    Variable Export Window
  4. After exporting, go back to the model and open the ‘Resource Usage Calculator’ Excel file (Right click on the ‘Resource Usage Calculator’ object and click on the second option from the bottom.
    Link to Resource Usage Calculator

    Click Enable Content if prompted

    Enable Macro

  5. Click ‘Calculate’. This may take anywhere from 30 seconds to 5 minutes, based on your computer’s processor and the number of resources.
    Resource Usage Calculator Calculate Button
  6. Once the calculations are done, you can goto individual resource workbooks and click on any of the day tabs to review resource usage data for that day. Individual resource usage files are saved in the same directory as the model. The file name starts with ‘UsageChart_’
    Resource Usage Calculator

Advance Topics

How would you find resource utilization of three resources in a Surgical Services scenario? Let’s go through an example Surgical Services model to find the resource utilization of three resources.

Download Surgical Services – Starting Model here

 

Surgical-Services-Starting-Model Image

Open the ‘Surgical Services – Starting Model’ and review the process flow. You will note that the three resources are being used at multiple locations, the process times of many of the activities are different, and there is no real way to know projected hourly resource usage. Simulate the model and review the Output Report to see the total resource utilization.
Resource Utilization Report Output Report

 

We will now use the Model Object (Resource Usage Calculator) to find the hourly resource usage. The following steps will help us add the model object and set it up;

  1. Open the ‘Surgical-Services-Starting-Model.’
  2. Open ‘Model Objects,’ find the ‘Resource Usage Calculator’ under the ‘Resources’ and ‘Insert’ into the model.
  3. Open the ‘Attributes, Variables & Scenarios’ window (Insert \ Attributes, Variables & Scenarios) and goto the ‘Scenario Parameters’ tab.
    1. Change the default value for s_ResName1 to Decon.
    2. Change the default value for s_ResName2 to Assy.
    3. Change the default value for s_ResName3-5 to Steril.
    4. Since we want the maximum resource quantity, we will leave s_ResMaxQty1-5 to the default of 10.
    5. Close the ‘Attributes, Variables & Scenarios’ window.
  4. Copy the scenario parameter (s_ResMaxQty#) to the quantity of the relevant resource.
    1. Place the ‘s_ResMaxQty#’ in the Capacity field of each Activity associated with the resource.
  5. Simulate the model.

If you would rather like to review the completed model, download Surgical Services here

Once the simulation completes, we will export variable data and use the ‘Resource Usage Calculator’ to calculate hourly resource usage. The following steps will help us calculate hourly resource usage.

  1. Open the Output Report (View \ Output Report).
  2. Click the second Excel icon to export variable data and then click ‘Save.’
    1. Do not rename the report.
    2. Save the report in the same folder as the model.
  3. Choose the variables ‘v_AveResInUse1-3’ and click ‘Export.’
  4. After exporting, go back to the model and open the ‘Resource Usage Calculator’ Excel file (Right click on the ‘Resource Usage Calculator’ object and click on the second option from the bottom).
  5. Click ‘Calculate’. This may take anywhere from 30 seconds to 5 minutes, based on your computer’s processor and the number of resources.
    Resource Usage Calculator Calculate Button
  6. Once the calculations are done, you can goto individual resource workbooks and click on any of the day tabs to review resource usage data for that day. Individual resource usage files are saved in the same directory as the model. The file name starts with ‘UsageChart_’
    Surgical-Services resource usage graph

What Does the Graph Mean?

whisker chart

A whisker plot shows show the range of samples taken during the model run. If 30 weeks were simulated, then the values for all thirty weeks would be shown for each hour of each day of the week. The whisker plot summarizes the information in an easy to understand format.

An “X” in the black bar identifies the mean.

The box-and-whisker, of course, shows you more than just four split groups. You can also see which way the data sway. For example, you can see if the number of resources is leaning toward or away from an additional resource requirement.

The plot helps to see the trend line for what is required; then shifts can then be overlaid to meet the requirement to cover the mean, 75 percent, or 100 percent statistics.

Knowing the range of resource requirements helps you determine the staffing to meet company goals. If there is a lot of variability during a shift, you might be willing to understaff during some hours and push the overage into subsequent hours. On the other hand, if the response time is critical to revenue and the revenue per item is high, then you might want to staff to the peak requirement.

After staffing is decided, try each option in the model to determine the suitability of the staffing to reach system goals.

How can I translate to shifts?