Category Archives: Operations Management

Qualifying a Worthy Problem

Great talk by Professor Gerald Brown on the last day of INFORMS. If you ever have a chance to hear him speak, take it. Slides from his talk, which started with some motivating examples of military OR, are available here.

5 steps to qualifying a worthy problem to study/solve:
1. What is the problem?
If you can’t describe the problem, how do you know there is one? How would you ever solve it? The client never gives an unambiguous problem description, so work to get to the heart of the matter. If you can describe the problem, move to step 2.

2. Why is this problem important?
Don’t waste your time on trivialities. If the problem is important, move to step 3.

3. How is this problem now solved?
Few problems are entirely ignored, so be sure to understand how the problem is currently solved to ensure you are providing adequate improvement. If you can do significantly better, move to step 4.

4. How will you solve this problem?
Up until now, “solving the problem” has been agnostic toward the type of analysis. Now, choose an appropriate methodology and ensure the problem is tractable.

5. How will you know when you have succeeded?
Answer this before you start solving. It’s difficult/impossible to succeed if the goal is constantly moving, so hammer out what success looks like for this problem.

On the Operations Job Market: Reflections and Insights

The pdf is available here. Written by Renyu (Philip) Zhang in April 2016 after receiving placement at NYU Shanghai. The discussion is tuned for students looking for placement in OM departments of business schools. The advice is not overly surprising, but rings true. One snippet:

Compared to the need and connection attributes, the communication attribute is more controllable by a PhD student. I want to emphasize again that, in order to excel on the OM job market, you have to be a great communicator to convince schools that you have the potential to become a good colleague, a good researcher, and a good teacher. You need to train yourself to become a great communicator through continuous practices, both in casual small talks and in formal seminar presentations/teaching/public speaking. To improve the communication skill in small talks, it is advised that you regularly attend some social events (including the ones during conferences) to practice talking with others. You should also learn from the great small-talkers. Your school may also offer some communication classes that you can take. Your objective should be that, after years of practices, any stranger that speaks with you would find you a delightful person to talk with. For presentation skills, I would recommend you take as many opportunities as possible to present in classes, seminars, and conferences. You can also learn some presentation skills by taking presentation classes and/or watching videos of great presentations in, e.g., YouTube or TED Talks. Your objective of the year-long presentation skill practice is that your presentation will be clear, engaging, technically solid, and broadly appealing to the audience not familiar with your work or even your area of study.

Thanks to Xuan Feng for sharing.

2017 Early-career Sustainable Operations Workshop

Re-posting the call for presentations from Professors Kraft and Agrawal:

Dear colleagues,

We are happy to announce that the 2017 Early-career Sustainable Operations workshop will be held March 3rd – 5th, 2017 at the Darden School of Business, University of Virginia.

The program will follow a format similar to the past two years, with a dinner to be held Friday night, followed by a full day of presentations and panels Saturday, and then a half day of presentations on Sunday. The conference is sponsored by the Darden School of Business, the McDonough School of Business at Georgetown University, and the Ray C. Anderson Center for Sustainable Business at the Georgia Tech Scheller College of Business.

The program committee includes Atalay Atasu (Georgia Tech), Eda Kemahlioglu-Ziya (NC State), Beril Toktay (Georgia Tech), Vishal Agrawal (Georgetown), and Tim Kraft (Darden). We plan to schedule 6-8 presentations on Saturday and 3-4 presentations on Sunday. We are inviting junior academics (untenured faculty) and PhD students who are interested in presenting to submit a 1-page abstract or a working paper, if one is available, to by November 4, 2016. Notice of acceptances will be sent by December 16, 2016. Ties will be broken in favor of full papers.

For more information or questions, please email Tim Kraft at or Vishal Agrawal at

Thank you!
Vishal and Tim

Tim Kraft
Assistant Professor
University of Virginia
Darden School of Business
Charlottesville, VA 22903

Vishal Agrawal
Associate Professor
McDonough School of Business
Georgetown University
Washington, D.C.

INFORMS 2016 Presentations

Nov. 14, 2016, 1:30 – 3:00 PM
Mind The Gap: Coordinating Energy Efficiency And Demand Response
Eric Webb, Owen Wu, Kyle D. Cattani, Kelley School of Business, Indiana University, Bloomington, IN

Nov. 15, 2016, 1:30 – 3:00 PM
Predicting Nurse Turnover And Its Impact On Staffing Decisions
Eric Webb, Kurt Bretthauer, Kelley School of Business, Indiana University, Bloomington, IN

Nov. 16, 2016, 12:45 – 2:15 PM
Linking Customer Behavior And Delay Announcements: Are Customers Really Rational?
Eric Webb, Qiuping Yu, Kurt M. Bretthauer, Kelley School of Business, Indiana University, Bloomington, IN

Nov. 16, 2016, 4:30 – 6:00 PM
Using Past Scores And Regularization To Create A Winning Nfl Betting Model
Eric Webb1, Wayne L. Winston2, 1Kelley School of Business, Indiana University, Bloomington, IN, 2Bauer College of Business, University of Houston, Houston, TX

Operational Thoughts on Fast Pass

fast pass

Businesses like to make money. Amusement parks are a business. I get those two premises. However, I observed a lot of operational issues with Fast Passes/Fast Track/Fast Lane tickets at the amusement parks on our trip.

Fast Passes/Tracks are upgrade purchases that guests can make at a park. The Fast Pass allows you to skip some or all of the line on some or all of the rides, depending on the park and the specific version of the upgrade that you buy. We saw prices that ranged from $50 at Michigan’s Adventure to $120 at Cedar Point.

1. Some implementations of the Fast Pass idea had two lines that merged into one prior to the ride. Presumably, the Fast Pass line is always shorter than the normal line. However, this implementation requires an employee to act as traffic cop when the lines merge, a job with little added value. Other implementations keep the distinct lines all the way up to the ride itself, whereby the typical ride employees can officiate how many Fast Pass riders to allow and how many normal riders to allow. I think the second option makes more sense. First, you don’t need the extra employee. Second, normal customers feel jealousy/aggravation when their line is stopped so that Fast Pass customers can literally line jump in front of them. There’s less aggravation if the merge occurs more seamlessly at the ride itself and normal customers do not have to wait with Fast Pass customers for an extended period.

2. Some rides were saving seats for Fast Pass riders, with the Fast Pass line coming up the exit ramp to the ride. All of the rides that did this were saving too much capacity for Fast Lane. Magnum XL-200 at Cedar Point (built in 1989) was saving 4 seats for Fast Pass riders on each train. Storm Runner at Hersheypark was saving close to half the train for Fast Pass riders. In my brief wait for each ride, I didn’t see anyone come up the Fast Pass line for either ride. As such, that capacity was being left empty on the train, to the annoyance of normal waiting customers. You should only save capacity that you can routinely fill. For older rides with little Fast Pass interest, I don’t see the point in saving any capacity.

3. From a customer point of view, I would rarely decide that it was worthwhile to purchase a Fast Pass. I routinely get on every ride (that interests me) at parks in a single day. Yes, occasionally a Fast Pass will save you a one-hour wait, but you can typically get on every ride without a Fast Pass. The exception would be if you are silly enough to goto a popular park on a Saturday in the summer. Then it is crowded, and you may need a Fast Pass to ride every ride.

I think strategic thinking in terms of park dynamics is almost as valuable as a Fast Pass, and it is free. If you want to minimize your wait for rides, do the opposite of what other guests are doing. Most guests work their way from the front of the park to the back. So if it’s early in the day, the rides in the back of the park will have shorter lines. Go there first. Many rides will have shorter waits during dinner time as customers stop for food and a break. If a park has a water park, it will become crowded in the mid-afternoon, taking riders away from normal coasters.

4. Are Fast Passes fair? It’s always frustrating when a person willing to pay for extra privileges gets to do something ahead of you, after you have been waiting. I am of the opinion that everyone should wait the same duration for the same ride (and I miss days gone by when Fast Passes didn’t exist). Having said that, I understand why parks offer them. They are a means of price discrimination, getting richer customers to pay more for a slightly better experience. If I were running a park, I would get rid of Fast Passes and make up the lost revenue by moving some concession stands to the longer queues of popular rides. Concessions are price-discriminatory as well, as richer customers are more likely to buy. I would think concessions would sell well in a line where customers don’t have much else to do but wait. Concessions are less attractive in the park at large, where customers can bypass them to get to the next attraction, game, or ride. Moving concessions to the queues of long lines will more than make up for the lost revenue from eliminating Fast Passes, and “normal” customers will not be as frustrated by the presence of concessions as they are by being jumped in line by wealthy park patrons with Fast Passes. After all, line jumping is cause for ejection from the park.

This discussion has been specific to the Fast Pass concepts I saw at the Cedar Fair parks and Hersheypark. I understand that Disney has a form of this as well, but it is free to everyone. I have never experienced Disney’s system myself, but from what I understand, it simply rewards strategic customers over non-strategic ones. Perhaps this is valuable to Disney because strategic customers like to game the line-skipping system and non-strategic customers don’t notice the ruse.

Busy busy busy

-I am sprinting to finish two papers (“Mind the Gap: Coordinating Energy Efficiency and Demand Response” and “Linking Customer Behavior and Delay Announcements: Are Customers Really Rational?”) by July 24.

-I am presenting the delay announcements paper at the Behavioral Operations Conference this Friday in Madison, WI.

-After the conference, Maria and I are doing an amusement park tour of the Great Lakes region: Michigan’s Adventure, Canada’s Wonderland, Hersheypark, Dorney Park, possibly Wildwater Kingdom, and Cedar Point. We’ll also stop in Indiana Dunes State Park, Chicago, Detroit, Niagara Falls, Philadelphia (for a Phillies game), and Cuyahoga Valley National Park. We’ll be back in Bloomington on July 26. During the trip, I’ll frequently be finalizing the two papers above while Maria drives.

-After I get back, I am sprinting again to re-submit “Incentive-Compatible Prehospital Triage in Emergency Medical Services” by mid-August.

-As such, there won’t be many website posts for the next month or so.

-After that, I will be working on a project inspecting the behavioral aspects of staffing and turnover, a new energy project, and finishing up my NFL betting project.

Call for Seminal Papers

As described on this page, I have started to collected a list of seminal papers in Operations Management and Information Systems. Seminal papers include classical results, well-cited results, and results that have inspired other research.

If you are a researcher or practitioner in OM, IS, or a related field, please consider sending me ( a list of 1-10 suggestions for seminal papers. I will add your suggestions to the posted list.


In addition to customers and suppliers, other groups of people also have an interest in the well-being (financial and otherwise) of an operation. Steakholders include employees and unions, the local community, social groups (such as vegetables’ rights or environmental concerns), government, and financial investors.

steakholder buffet

Book Review- Managing Operations Across the Supply Chain

Managing Operations Across the Supply Chain, 2nd Edition
by Morgan Swink, Steven A. Melnyk, M. Bixby Cooper, and Janet L. Hartley, 2014

Managing Operations Across the Supply Chain

I used this book for my undergraduate class at IU, Introduction to Operations Management. It was taught for business minors, and this book offers a good, non-technical introduction. I looked at a few other books for the course, and this was the most appropriate option. It has good break-outs of the experience of individual companies in each chapter. That being said, the exposition can be dry and certain sections spend too long trying to explain technical topics without upper level mathematics.

I covered Chapters 1-12 and Chapter 15 for my class. I mostly created my own questions for homeworks and tests, though a few multiple choice problems were taken from the test bank provided with the text. I also added a few in-class activities and a section on Behavioral Operations Management to the course that fell outside the text.

Intersection of Behavioral Operations and Energy

An intersection I am very interested in with my research interests. From an interview with Tendril CEO Adrian Tuck:

Under today’s demand response — whether you are turning someone’s air conditioning off or sending them a message to do something else — you are really just making a problem on the network the customer’s problem. Nobody else does that.

Netflix is an example that I often use. Netflix often has huge capacity-constraint issues, but they don’t tell you not to watch a movie on Saturday night or charge you more during a peak time. They just do really clever things behind the scenes. It might take slightly longer to spool the movie up on a Saturday night than it does on a Tuesday morning, or the pixelation on the movie is not quite as good as it would be — but they manage all of that to ensure the service.

The utility equivalent would be to tell people not to watch a movie on Saturday night. I think a fixed-price model — say $200 per month based on what you use — is better than a time-of-use rate. Time-of-use just takes a problem on the network and makes it a customer’s problem. I think the company that uses all these smart technologies to deliver a flat price of energy, and to take away demand response or time-of-use, is going to succeed in the market.