Modeling fraud in the financial system
Today we have a guest post by Dan Tedder. Actually it’s a letter he sent me after listening to my EconTalk podcast with Russ Roberts which he kindly agreed to let me post. Dan’s bio is below the letter.
I think this letter is profound (although I don’t completely agree about the Markov stuff), because it points out something that I see as a commonly held blindspot by people who think about regulation and modeling. Namely, that any systemic risk model of the financial system that doesn’t take account of lying isn’t worth the memory it takes up on a computer.
That brings us to the following question: can we incorporate lies into models? Can we anticipate and model fraud itself, in addition to the underlying system? Or do we give up on models and rely on skeptical people to ferret out lies? Or possibly some hybrid?
I really liked your interview, and I think you are right on in pointing to a lack of ethics. I would say further that what we need is rigorous honesty in all aspects of the financial system. I agree with your objections to conflicts of interest. Allowing such conflicts to exist demonstrates a lack of rigorous honesty on the part of the participants. In my opinion a lot of bankers and folks on Wall Street should be headed to jail. The inability of the SEC to file charges and prosecute them further demonstrates the lack of honesty and character in the financial system and the government. So why am I telling you things you already know?
My father was a successful businessman. Years ago I was invited to invest in an ice cream franchise by another faculty member. I spent several days developing models using Excel. Finally, I decided to talk to my father. I called him and he immediately asked me to tell him about the present owners and their accounting. I told him the husband was in jail and accounting was five years behind. Further, his wife was probably taking money out of the till.
He stopped me right there, and pointed out that I needed to look no further. The present owners were not honest and therefore the opportunity was too risky. No telling what liabilities they had incurred and passed on to the franchise. I felt like an idiot. My modeling was a total waste of time because it assumed the present owners were honest. In fact, they were dishonest and no defensible model could be constructed based upon their accounting or lack thereof.
I think the complexity of our present financial problems will largely disappear if we try to focus more on the obvious. First, it is obvious that bankers, accountants, modelers, and other participants must be rigorously honest. Second, George Box, a statistician at the University of Wisconsin, studied the stock market and found through time series analysis that stock market prices are Markov processes. So in modeling stock prices we need only worry about today and tomorrow. The best indicator of tomorrow’s price is today’s price. The best indicator of what will happen tomorrow is where we are today, and probably our models of the larger process should also be Markovian. Third, apply the KISS method, “Keep it simple, stupid.” Instead of worrying about the mathematical model, worry about the honesty of the participants. The financial system cannot tolerate dishonesty. Making sure the bankers are honest will go a long way toward balancing the books.
Daniel William Tedder is Associate Professor Emeritus, School of Chemical and Biomolecular Engineering, and Adjunct Professor, School of Mechanical Engineering, both at the Georgia Institute of Technology. He attended Kenyon College and received a Bachelor’s in Chemical Engineering at the Georgia Institute of Technology. He obtained MS and PhD degrees in Chemical Engineering at the University of Wisconsin, Madison. He was a staff engineer in the Chemical Technology Division of the Oak Ridge National Laboratory before joining the faculty at Georgia Tech. He served as an independent technical reviewer at the Nuclear Regulatory Commission after retiring from Georgia Tech. He has numerous publications, has edited 11 books, and has authored one book, Preliminary Chemical Process Design and Economics, which is available from Amazon. He is an expert in chemical separations and in actinide partitioning, an advanced method for radioactive waste management.