Computer Models and the Global Economic Crash

Anti-Globalism passes along a review in Ars of some recent speculation on the role of interconnected computer models in the global economic crash. "If Ritholtz, Taleb, Mandelbrot, and the rest of the computer modeling and financial engineering naysayers are correct about the big picture, then we really are arguably in the midst a bona fide computer crash. Not an individual computer crash, of course, but a computer crash in the sense of Sun Microsystems' erstwhile marketing slogan, 'the network is the computer.' That is, we have all of these machines in different sectors of the economy, and we've networked all of them together either directly (via an actual network) or indirectly (by using the collective 'output' of machines in one sector as input for the machines in another sector), and like any other computer system the whole thing hums along nicely... up until the point when it doesn't."

Comments

Can somebody 'splain this?

[seanadams.com]

I am not an economist but I have owned a couple businesses and consider myself a reasonably practical person.

I have always believed that the vast majority of today's financial instruments have been invented out of thin air for no reason other than to ultimately ensure the employment of bankers and brokers.

For example, lots of people have a checking account, savings account, credit card, poersonal line of credit, HELOC, brokerage account, and more. I see absolutely no reason why a single account could not offer all those features. The only reason you "need" all that is because the banks created all these funny rules so that they could introduce more and more products and services. This is done so they can charge you more for each of those things, and also to differentiate them from their competitors.

Besides consumer banking, can somebody explain to me why we NEED "commercial paper"? Yes, I've read the wikipedia page and I know how it's used, but I don't understand why it's needed. If you can't make payroll then you're pulling from your credit one way or another - why do we need separate instruments for a 2 week loan versus a longer term loan, or a credit card, or whatever?

And don't even get me started on real estate lending...

It's like freaking starbucks - you can get your banking services just as special as an upside-down triple no foam half calf non fat 160 degree two splenda mocha. But it's one thing for a coffee company to cater to every individual snowflake's desire, and quite another IMHO for something as important as our financial system to become as absurdly complex and fragile as it is.

As for the people who are really benefitting from all this complexity - well, it's only during recession that we all collectively take a good hard look at who's making a contribution to society and who isn't. Unfortunately the powers that be think they can beat a recession by tweaking some rates, stealing from taxpayers, or shuffling money from one hand to the other. That's just going to hurt us more in the long term. We need to clean this shit up now - get rid of unnecessary products and overhead, and let the unproductive companies go bankrupt. Let the UAW strangle themselves to death. Just get it done.

Re:Can somebody 'splain this?

[hey!]

For example, lots of people have a checking account, savings account, credit card, poersonal line of credit, HELOC, brokerage account, and more. I see absolutely no reason why a single account could not offer all those features.

Neither did advocates of banking deregulation in the 1990s.

One of the reasons for this "redundancy" is (or used to be) that different rules apply to each kind of account. You used to have have commercial banks, investment banks, and insurance companies, and each did something different under different rules. Then the rules that had been in place since the Great Depression were repealed by Gramm-Leach-Bliley, and suddenly the legal boundaries between these kinds of financial services was gone.

Subsequently, we are facing the greatest economic crisis since the Great Depression. Coincidence? I'm not entirely sure, but surely some of the problem is that practices and attitudes that were normal in investment banking suddenly started to crop up in other businesses.

Although Hank Paulson is actually, in my opinion, one of the more decent individuals as a person in the administration, he's very much the wrong man at the wrong time. One of the things he did as head of Goldman Sachs was to convince the SEC to get rid of the "net capital rule". That was the rule that required banks to maintain a certain level of cash on hand to cover cash demands in unusual situations. This is obviously extremely expensive for companies who had to keep huge volumes of cash on hand, losing mind boggling amounts of value even against modest inflation.

Had the rule been kept in place, we might not have had to pony up seven hundred billion dollars to bail out Wall Street.

Re:pointing fingers

[AJWM]

Two words: "emergent behaviour".

No one group of programmers programmed all these computers, there was no single set of specs for the whole network. All the components may well be "functioning exactly as they should be" (although in reality I'm sure there are a few bugs in the systems, but that's irrelevant here), but the system overall may behave in an unexpected way.

(That said, I don't think that's the whole problem either -- too many people playing a bit fast and loose and less than honestly with other people's money is also part of the problem.)

Re:pointing fingers

[BigTom]

What is tightly regulated? Half the Quant algo trading models get thought up in the evening, coded overnight and activated in the market the next morning.

If you try and slow them down they just run to the head of the desk bleating that the "nasty IT man stopped me making $1000,000,000 for the bank with his silly QA nonsense" and whoosh, its in production. It is prop trading so its their risk.

Can't model in human traits

[HW_Hack]

How can you model in greed - corruption - and the ever popular human trait of freaking out ?

Tech bubble - Real Estate bubble ... next time I even see/hear the word bubble in the markets I'm cashing out for a while

The model assumptions were ideological

[grandpa-geek]

There are two equally valid descriptions of markets. One is by Adam Smith, with the "unseen hand" guiding the markets. Smith markets are well behaved, efficient, and amenable to analysis by what amount to small-signal statistics.

The other description is by Charles Mackay in his book "Extraordinary Popular Delusions and the Madness of Crowds." In that book he describes the Dutch tulip craze and other bubbles in history prior to the mid 1800's. This economic crash is more of the same.

The models, probably because of "free market" ideology, assume a market where Adam Smith's "unseen hand" is at work. The modelers don't consider the kinds of markets described by Charles Mackay. Most of the models are based on the Black-Scholes option pricing theory. If you look at the assumptions underlying that theory, they describe good behavior, efficiency, and changes describable by what amount to small-signal statistics.

Mackay markets are boom and bust, with greed and lies and herd behavior all around. That's what we had. The underlying mathematics has been studied, but not for markets. If you have a pre-LCD TV, an electronic circuit that is non-statistical but related to boom-and-bust market behavior creates the sawtooth sweeps that paint the picture onto your screen.