Tuesday, November 4, 2008

ORdinary Spreadsheets and ORdnances

The July-August 2008 Interfaces Journal ran a theme of "The Use of Spreadsheet Software in the Application of Management Science and Operations Research". In their article from that issue, "A Spreadsheet Implementation of an Ammunition Requirements Planning Model for the Canadian Army", Hurley and Balez describe a successful spreadsheet model for planning training ammunition expenditures.

Ammunition is expended in training courses in a highly uncertain environment. Course registration rates, failure rates (before completing the entire course), and other uncertainties make it difficult to accurately forecast ammunition consumption. Planners must choose a course portfolio that will not result in an ammunition shortage. Of course, to minimize the chances of running out of ammo, planners to date had been planning to the maximum expenditure per course. The consequence of this was that the program came repeatedly under budget, 38.7% in 2002-03. This is far from ideal when attempting to allocate scare resources. Naturally this was an opportunity to apply risk management principles in order to either request a smaller budget to accomplish the same goals or to do more with the same budget.

The solution took the form of a spreadsheet tool. The Excel spreadsheet combined with Visual Basic for Applications (VBA) provided an easy and inuitive interface for planners to interact with the risk model. As a result, in 2004-05 the program was only 3.1% under budget. I will not go into too many more details as they are available in the article, but I had two interesting thoughts:

[1] A big advantage of using spreadsheets is the familiarity most managers have with it. Leveraging this, the team built a simple spreadsheet simulation to demonstrate the portfolio effect of running several courses. With repeated "F9-Simulations" (my term) they were able to demonstrate that while 10 course sections will never use 10 times the maximum (as presently budgeted), it is actually reliably much less than this. Moving up a level and using @Risk to run 10,000 simulations they were able to convincingly demonstrate the concept.
We cannot overemphasize the value of this type of spreadsheet demonstration in selling the potential of an OR model.
Interestingly enough their experience differs from my own. I tried to convince an utlrasound department supervisor that if average-45-minute appointments of uncertain lengths are booked every 45 minutes, her technologists would reliably work overtime. To do this I built a simple spreadsheet simulation, but it was totally lost on her. This is not meant as a knock against this approach, but rather to emphasize the importance of manager familiarity with spreadsheets. My ultrasound supervisor as a senior medical radiation technologist thinks differently from a rising Canadian Colonel.

[2] When selecting a portfolio of courses to fit the approved budget (less than requested), the Army chose to manually optimize using the tool rather than accept a priority-optimized result from a linear program. This perplexed the authours and I think they wrongly blamed themselves for a failure to achieve buy-in. It is my experience that when dealing with problems of a magnitude that an individual can wrap their heads around, clients prefer to leverage their intuition and optimize by hand. As OR practitioners we may not trust the client to acheive a truly optimal result, but as a client they do not trust a model to capture all of the nuances they know inuitively and the answer, of course, is somewhere in between.

The idea of doing OR with Excel probably wasn't what got you started in the field, but if you like seeing results it might just keep you in it.

Hurley, W.J., Balez, Mathieu. 2008. A Spreadsheet Implementation of an Ammunition Requirements Planning Model for the Canadian Army. Interfaces 38(4) 271-280

Monday, November 3, 2008

Computer Age Workers Suffer Digital Fatigue - Can OR Help?

The October/November Issue of Scientific American Mind magazine highlights the increasing digital fatigue we are facing as a result of always being plugged into technology.

According to a study conducted by the article's authors, our neural circuitry is actually rewired as we become more computer savvy. Internet-naive subjects, after only five consecutive days of internet use (one hour/day), had already (unconsciously, of course) rewired their brains to match those of the computer-savvy subjects in the study.

While the prospect of adapting our brains to optimize our use of the internet may sound exciting, the authors warn that the computer age has plunged us into a state of "continuous partial attention" - which they describe as keeping tabs on everything, while never truly focusing on anything.

This can result, according to the authors, in a state of "techno-brain burnout", where people place their brain in a heightened state of stress by paying continuous partial attention to anything and everything. Because our brains were not built to sustain this level of monitoring for such extended periods of time, this "techno-brain burnout" is threatening to become an epidemic.

While these heightened stress levels can have short-term productivity benefits, they are proving to be significant hindrances to medium-long term productivity, due to worker fatigue and inability to concentrate.

So where does OR come in? Well, let's review the characteristics of this vexing problem to the computer age, with workers who:
  • Have too much to do, too little time
  • Are overwhelmed by incoming stimuli
  • Fatigued and drained
Perhaps an old school approach - from the early days of scientific management - could be the right prescription.

Our old friend Frank Gilbreth, father of motion study, on his second day on the job as a bricklayer, questioned why he was being taught several different methods for laying bricks. So Frank developed motion and fatigue study, and created a process for laying bricks that was vastly more efficient than the processes currently in place.

In fact, Frank's new method increased productivity by nearly 200%, while simultaneously reducing worker fatigue. Here's a nice two-minute overview of Frank's bricklaying study from YouTube - a nice refresher course if it's been awhile:

It seems that computer age workers could greatly benefit from motion study analysis - and who better to deliver it than OR practitioners?

If you walked into a factory, and saw everyone on the assembly line improvising and doing their job any way they pleased, without any knowledge of best practices or recommended techniques, wouldn't you be stunned? Yet to this point in time, this is how the computer age workforce operates.

Time management and productivity experts have been at the forefront of efforts to tackle these problems, but their recommendations are usually fairly general, and without quantification. While advice such as "don't check email first thing in the morning" may indeed be worth practicing, eventually, we should be able to help guide specific individuals and workers to their optimal level of productivity.

And if that isn't ripe for OR, I don't know what is.