University of Maryland
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The Computer Integrated Manufacturing Laboratory is a constituent laboratory of the Institute for Systems Research at the University of Maryland.

Frequently Asked Questions


The outputs talk about staffing required per shift, but the model does not state how many shifts are used per 24 hours. How do I convert the model output into the number of people needed per 24 hours?
The clinic planning model evaluates the performance in steady-state at a particular point in time. Multiple shifts per day mean multiple groups of people if each group works one shift per day. For instance, suppose the POD has 2 12-hour shifts (day, night). 70 people per shift means 70 people working the day shift, and 70 more work the night shift, for 2 x 70 = 140 people.

New Versions

What is new about Version 2.04?
Version 2.04 fixes some minor bugs in 2.03, including updated queueing approximations for estimating the queueing time at each station. It also changes the input information needed for the clinic arrival process to make it simpler and more intuitive.

What is new about Version 2.03?
Version 2.03 has two major enhancements. First, it allows one to model a self-service station, where a patient performs the process by himself. Second, it has new queueing approximations for estimating the queueing time at each station.

What is new about Version 1.25?
Version 1.25 corrects an error that could occur when using a batch process station. It also enhances the user interface and allows the user to define the staff positions in the clinic.


Is it necessary to register?
No, it is not required. If you register, we will update you when revisions are available.

Will I get junk email from you if I register?
No. We will not send you junk email and will not share your email address with anyone.

Downloading and Installing the Software

Why do I get an error when I go to save the clinic model?
It is essential to have both the Clinic Generator and Clinic Template files in the same folder on your computer when using the software. In addition, some users have had trouble when these files are on the Windows Desktop. We recommend placing them in My Documents or some other folder. See also the next two questions.

Does hiding file extensions cause a problem?
The problem may be that Windows XP will hide extensions of known files, hence the Clinic Planning Model Generator will not find the correct filename Clinic Template.xls. One of two things may happen: either the user adds a .xls extension to Clinic Template making the effective filename Clinic Template.xls.xls; or the file extension was truncated. To fix the problem:

  1. Open the folder containing the Clinic Generator 1.25 files
  2. From the menu, go to: Tools>>Folder Options...
  3. Select the "View" tab
  4. Scroll down the list of "Advanced Settings:" and find "Hide extensions for known file types"
  5. Uncheck the box to disable this function and click "OK" At this point, the user will be returned to the Clinic Generator 1.25 folder with the files and its file extensions revealed.
  6. Right click the file with "Clinic Template" in its name and select "Rename"
  7. Delete the entire name and type in "Clinic Template.xls"
  8. Hit "Enter" Key, click "Yes" if warned about changing the file name extension.

The Clinic Planning Model should work correctly after following the procedures. It will continue to function if the user chooses to enable "Hide extensions for known file types."

Do I need a specific version of Microsoft Office?
No. The software was designed to be used with any version of Microsoft Office. However, some users have reported resolving problems when using Office 2000 by upgrading to Office 2003.

Preparing a clinic model

Can I get copies of the forms in Appendix A?
Yes. Appendix A is available as a Microsoft Word document.

Using a clinic model

Do I need to enable macros?
Yes. If you get a security warning about the spreadsheet, you do need to enable macros. Macros are used to create the clinic planning model and for moving from one sheet to another and to reset all staff to the minimum.

Why won't Microsoft Excel run the macros? Note: If running Microsoft Excel 2003, you may need to change the Macro Security level to Medium. On the Excel Tools menu, click Options. Click the Security tab. Under Security, click Macro Security. Click the Security Level tab, and then click on the button next to Medium. Then click OK.

Why do I get negative numbers?
Negative numbers usually indicate that the utilization of one or more stations is greater than 1. This means that the clinic has an insufficient number of staff at those stations. Increase the number of staff at any station that has utilization greater than 1.

What is clinic capacity?
Clinic capacity is the maximum number of patients per hour that the clinic can serve. This is based on the capacity of the stations and the routing of patients through the clinic. The clinic capacity should be larger than the required throughput in the input demands section..

If you have a question not answered here, please contact Dr. Jeffrey W. Herrmann at or 301-405-5433.

Last updated by Jeffrey W. Herrmann, June 9, 2011.

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