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Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.
Your question implies that you think physicists could utilize their skills/knowledge to provide more successful theories/models of finance. I'm an engineer, not a physicist, but I suspect physicists are more confident in the motion of the planets than the markets because gravity is more reliable than human behavior.beamthegreat said:What do physicist think of the efficient market hypothesis?
Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.
Well, physics is indeed able to tell that if you nuke it the value will fall.beamthegreat said:Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.
russ_watters said:Your question implies that you think physicists could utilize their skills/knowledge to provide more successful theories/models of finance. I'm an engineer, not a physicist, but I suspect physicists are more confident in the motion of the planets than the markets because gravity is more reliable than human behavior.
BWV said:at least as strong as gravity
But it kills more people every year than any other fundamental interaction...etotheipi said:Besides the point, but I thought I'd point out that as fundamental interactions go, gravity is extraordinarily weak
Human behavior on an individual level is quite unreliable. But maybe the behavior of billions of humans can be modeled reliably like we do for, say, a perfect gas. Maybe, maybe not. A billion is a big number but nowhere near as big as 6*10^23.russ_watters said:but I suspect physicists are more confident in the motion of the planets than the markets because gravity is more reliable than human behavior
Is your assumption that the EMH is true or false, by the way?beamthegreat said:Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.
To paraphrase (and butcher) Douglas Adams: it’s not the gravity that kills you, but the sudden electron-electron repulsion at the end.BWV said:But it kills more people every year than any other fundamental interaction...
beamthegreat said:Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.
russ_watters said:Your question implies that you think physicists could utilize their skills/knowledge to provide more successful theories/models of finance. I'm an engineer, not a physicist, but I suspect physicists are more confident in the motion of the planets than the markets because gravity is more reliable than human behavior.
Very interesting discussion.bobob said:Some of the biggest employers of mathematicians and physicists are investment banks and hedge funds. They don't rely on human behaviour beyond detailed statitical analysis from real data, not any presumptions or preconceptions about how humans behave. Their trading is algorithmic and you would be surprised at the kinds of things they connect as derivitives (such as hotel occupancy and predicted cloud cover) and their trading times depend on making trades in milliseconds. There is not much difference between modeling planets and modeling markets from a data driven perspective. You collect data and derive a model. That is precisely why investment banks and hedge funds hire physicists and mathematicians as quants.
Renaissance Technologies will not even hire people with an economics or investment background.
It was clear from the beginning that the central question is whether asset prices refect all available information—what I labeled the efficient markets hypothesis (Fama 1965b). The difficulty is making the hypothesis testable. We can’t test whether the market does what it is supposed to do unless we specify what it is supposed to do. In other words, we need an asset pricing model, a model that specifies the characteristics of rational expected asset returns in a market equilibrium. Tests of efficiency basically test whether the properties of expected returns implied by the assumed model of market equilibrium are observed in actual returns. If the tests reject, we don’t know whether the problem is an inefficient market or a bad model of market equilibrium. Tis is the joint hypothesis problem emphasized in Fama (1970). A bit of notation makes the point precise. Suppose time is discreet, and Pt+1 is the vector of payoffs at time t + 1 (prices plus dividends and interest payments) on the assets available at t. Suppose f(Pt+1⎪Θtm) is the joint distribution of asset payoffs at t + 1 implied by the time t information set Θtm used in the market to set Pt , the vector of equilibrium prices for assets at time t. Finally, suppose f(Pt+1⎪Θt ) is the distribution of payoffs implied by all information available at t, Θt ; or more pertinently, f(Pt+1⎪Θt ) is the distribution from which prices at t + 1 will be drawn. The market efficiency hypothesis that prices at t reflect all available information is, (1) f(Pt+1⎪Θtm) = f(Pt+1⎪Θt ).
I have a masters degree in statistics. In my opinion the efficient market hypothesis is a useful first order approximation of what actually goes on. There is much research these days of ways in which people deviate from mathematically correct rational behavior. On the other hand since it but an approximation I am distrustful of towers of mathematics constructed on this infirm foundation.beamthegreat said:Just wanted a fresh perspective on this considering that physics is more successful at modeling reality compared to finance.