Showing posts with label simulation. Show all posts
Showing posts with label simulation. Show all posts

Thursday, April 26, 2007

Information Technology, Systems, and Simulation

Some years ago, a time sufficiently distant that I was still a member of the IEEE (Institute of Electrical and Electronics Engineers) I attended one of that organization’s Simulation Conferences. I there heard an anecdotal tale from two engineers, who had prepared a queuing model for a particular warehouse operation. The model had the unfortunate tendency to fail with some regularity; the simulation would progress to a particular point and then cease to function, responding with a series of error messages.

The two engineers decided to visit the site of the warehouse that they were simulating, in order to observe a day at the loading dock, which was the input to the queuing model. They observed the following sequence:

  • A truck arrived at the loading dock.

  • The driver and dock attendant began unloading the truck, whose cargo was a number of cardboard boxes, all of identical size.

  • As each box was unloaded, it was placed on a moving conveyor belt, which transported the boxes into an automated stacking system within the warehouse.

  • When the final cardboard box was placed on the conveyor belt, the dock attendant also mounted the conveyor belt, and when it reached the entrance to the warehouse, he proceeded to kick and pummel the box until it entered the warehouse.


  • The engineers were nonplussed. “Why did you just do that?” they asked the dock attendant. The dock attendant then explained that there had been a blueprint error in the construction of the warehouse and the storage area that fed the automated stacking system was about nine inches too short, so it was necessary to force the last box into the warehouse. The boxes in the storage area had just enough give for that task to be accomplished, provided some substantial force was applied to the last box.

    In a sense, then, the simulation had been a success. The automated warehouse system would fail if used as constructed. However, human intervention has compensated for what was basically a defective system design.

    In recent years, a substantial portion of the productivity gains in the U.S. economy have been ascribed to Information Technology (IT) as the causal agent. There is probably substantial truth to this conjecture, especially if IT is expanded to include telecommunications of all sorts, email, cellular telephone technology, broadband internet connections, etc. However, there are a number of implications to heavy IT involvement on business processes that should be borne in mind. I will speak primarily to two such implications. The first is that a high degree of IT involvement in a business tends to make that business “system centric” as opposed to “process centric.” There are several further implications of that observation, and I’ll get to those in a bit.

    The second thing to bear in mind is that IT systems are generally simulations of something, rather than res ipsa “the thing itself.” This is easy to see when we speak of a computer simulation model, but this hardly scratches the surface. A telephone, for example, does not deliver the voice of the person at the other end; rather, electrical information is sent from one place to another that then allows a simulated human voice to appear at the receiving end. Similarly, financial and accounting systems are simulations, and economists speak of “the financial economy” as different from “the real economy.” When decisions made for financial accounting reasons are derided as “coming from the bean counters,” that derision carries with it the idea that the financial simulation is missing some important part of the real situation.

    Nevertheless, accountants and financial officers are charged with protecting the financial systems of an organization, and with good reason; if the financial system fails, it likely mirrors a failure in the “real” organization, and even if it does not, financial system failure makes some part of the real organization either unobservable or uncontrollable, or both. As is often the case, financial systems are both simulation systems and control systems.

    The same may be said for IT systems. IT systems are generally either communications or control systems (or both), and failure of an IT system can have adverse or even catastrophic consequences, whether it be losing an inventory database, sensitive customer information, or a set of emails. Without adequate information, management decisions become mere guesses, and without adequate communications, those decisions cannot be implemented.

    Moreover, as the tale of the automated warehouse suggests, IT systems are not as robust as real processes, because human beings are inherently more adaptable than algorithms and hardware. If the box doesn’t fit, the dock foreman may try kicking it; if that doesn’t work, perhaps a box cutter will do. If that fails, then perhaps he stores the box temporarily, until the holding area clears. As long as a human being has a goal in mind, he or she will often find away around obstacles. There is even a common name for this: “work-arounds.”

    So it is understandable, perhaps even inevitable, that IT organizations will tend to become “system-centric,” but this carries numerous drawbacks. The obvious drawback is the tendency to concentrate of system development at the expense of business process development. This has several follow-on failure modes.

    First, concentrating on systems rather than process tends to starve the processes themselves of needed resources. This is particularly problematic in a cost-cutting environment, where IT systems are, in themselves, supposed to reduce the need for personnel. Too often, however, the personnel savings are assumed rather than demonstrated, with an outcome that is deleterious to the underlying process. Moreover, IT systems usually carry their own overhead burdens, so it is not uncommon to see the effect of merely trading one set of employees for another set, the latter often being more expensive than the former. This, incidentally, is a problem that is not at all confined to IT. It is often true that attempts to implement cost-cutting through personnel reduction results in an increase in managerial overhead (“off-shoring” projects are notorious in this regard) to no great benefit to the organization as a whole. Hospital management is another area where this phenomenon has been observed, with reductions in nurse-to-patient ratios often occurring simultaneous to substantial increases in administrative (and sometimes legal) overhead.

    Another implication of “system-centricity” is that it allows, even encourages, “gaming the system.” A substantial portion of the enhanced productivity created by IT systems in large organizations is the deletion of several layers of middle management. The managerial review process is then replaced with a variety of system-derived “metrics.” However, employees then often find it easier to “work the metric,” than to perform the work that the metric is supposed to reflect. This is the equivalent of the use of standardized testing in the public school system. Given the need for a certain percentage of students to achieve particular scores on the tests, teachers find themselves under pressure to “teach to the test,” emphasizing material that is known to be on the tests and de-emphasizing material which either does not appear on the tests, or material for which it is inherently difficult to test. In some cases, school administrators and teachers have been found restricting the student population that takes the tests, sending those who will do poorly home on test days. In other cases, there has been instructor assisted cheating.

    There are no easy answers or quick fixes to these problems. Certainly the older “thick middle management” model contained its own pitfalls and cannot be taken as a model of information clarity and inevitably sound judgment. If higher level managers wish to be kept ignorant of problems within the organization, they will accomplish this task, whether by killing the messengers bearing bad news, promoting those who tell flattering lies, or receiving “dashboards” that do not adequately convey a picture of the organization. However, those wishing to be dutiful officers and representatives of the organization as a whole, should listen to the whispered memento mori (“Remember Thou art Mortal”) and take heed.

    Wednesday, February 28, 2007

    This Year’s Model I

    I’ve been asked to write a few things about models and modeling, as that is (in theory at least) my core area of expertise. Before I get to the cool stuff, the computer simulation models that I’ve spent at least 25 of the last 35 years working with, I’m going to “go meta” for a bit.

    The word “model” in the most general sense in science is very, very broad, and can be applied to almost anything. In fact, any abstraction is a “model” of something else, as is any analogy, simile, theory, or description. This almost, but not quite, makes the general sense of model so general as to be useless.

    At this high level of abstraction, even the idea of “fact” becomes a theory. Indeed, it’s pretty hard to find an instrument or even a sensory experience, that doesn’t depend upon some theoretical construct for its meaning and interpretation. So “meaning” becomes a model, as does “language,” and “thought.” That’s what Plato was getting at when he was babbling about shadows on the cave wall. Reality itself is a theoretical construct.

    In the recent past, Steve Gillette and I have had a few back and forths that touch on this area when we were discussing “brute facts” vs “institutional facts.” That division is similar to the “analytic” vs “synthetic” distinction suggested by the Positivists (who rewrote a page out of Kant). It’s also possible to map “analytic” to “deductive” and “synthetic” to “inductive.” The basic idea is that there are certain sorts of propositions (or facts) that are derived from a priori definitions, using logic to derive propositions of greater and greater complexity. These are analytic/deductive/institutional propositions/facts. Then there are other sorts of propositions/facts that must take the sensory world into account in their formulation. These are synthetic/inductive/brute facts.

    One of the big arguments that this sort of talk produces is that it suggests that mathematics is an invention, similar to, for example, the law, or musical theater. Some mathematicians claim instead that mathematics has objective reality. I’ll only note that the best mathematician I know personally is of the strong opinion that mathematics is a human invention.

    Grind this grist fine enough and you get back to basic epistemology and questions about the nature of reality. Fine. I consider my position on the matter to be entirely defensible, but recognize that it seems to be hard to get across to some people. I once had a fairly lengthy online exchange with someone where I was trying to get across to him the difference between an abstract concept that the concrete reality that the concept might cloak. Consider a three-sided load bearing structure that we call a truss. One might very well locate a fossil, or a geological formation that can be said to be a three-sided load bearing structure. Was it a truss a million years ago? He insisted that it was, completely oblivious to my suggesting that “truss” is a human invention, and without humans, no truss exists.

    I know, I know, a pointless argument, except maybe not, because it is a trap to believe that concepts exist apart from the conceiver. The sentence “If a tree falls in the forest, does it make a sound?” is a Zen koan, actually, and, contrary to common belief, koans often have answers. In this case, the answer is, “The one I’m thinking of did.”