Econometrics is neither the source of scientific nirvana nor the ultimate in deluded alienation. It has its usefulness if kept in perspective. By itself it neither proves nor disproves anything. However, just as repeated findings pointing in a certain direction by experimental economists, such as that of the asymmetry between willingness to pay for improvements and willingness to accept compensation for degradations, eventually come to influence the views of the profession and even of policymakers, likewise repeated findings by econometric studies without contradicting findings have similar influence. Now, I find it a bit amusing that Doug Henwood has climbed the barricades against econometrics. It is one thing to criticize all empirical approaches to economics, and there are serious philosophical grounds for doing so. But Doug is our ultimate datameister/wonk. He presumably takes empirical observation seriously. However, he wishes to restrict the analysis of such data to eyeballing tables or maybe at the most scatter diagrams. As I have already noted, such approaches can be very misleading and are essentially equivalent to applying very rudimentary econometric tests, such as bivariate OLS regressions. Now, there is a horrible fascination in the profession with ever more "sophisticated" econometric methods. Much of this reflects the game of publishing to avoid perishing. Thus, every time a new technique pops up, such as cointegration (to Di Nardo, I agree with Peter Dorman that checking that one out more thoroughly would be useful), a bunch of fresh-out-of- grad-school-and-seeking-tenure economists begin applying it to all kinds of already-tortured-past-death (but updated slightly) data sets to study all kinds of also already beaten to death old questions. Ah ha! Publications! Tenure! Actually I think that Doug is at least partly right. Whenever there is a real shift in policy or broad viewpoint it is generally because something has happened in the data that is so screamingly obvious that it does not need any fancy econometric tests to establish it. If it can't be seen by the eyeball, the Board of Governors will not believe it. Indeed, the issue of monetarism is a good example. There was a long and gory econometric debate over "Keynesian fiscal policy" versus "Friedmanite monetarism" back in the 1960s, using the then currently fashionable sets of supposedly advanced econometric methods (sorry to whomever asked, I don't have the exact cites), mostly in leading mainstream journals. Donald Hester was a leader on the "Keynesian" side while Friedman with his former grad student, David Meiselman, were leaders on the monetarist side. The issue was: which is more stable, the marginal propensity to consume or the velocity of money (M1)? The debate was long and essentially inconclusive. Then in 1968 LBJ attempted to fight inflationary pressures by instituting a one-year income tax surcharge. It failed and this was used by observers to declare a victory for Friedman and a defeat for Keynes. In the same year, Friedman gave his AEA address on the "natural rate of unemployment" which has since uttlerly infiltrated all the macro textbooks, and which fed easily into the new classical/rational expectations movement that took over much of mainstream macroeconomics in the 1970s, further stimulated by the oil price shock inflation. Of course, ironically, Lucas actually explained why the LBJ tax increase did not stifle inflation. Policymakers relying on a structural econometric model for policy forecasting cannot do so if their actions change people's expectations and thus (in effect) change the values of the coefficients in the models. The announcement that the tax increase was only temporary had such an expectational effect, and one useful outcome of the whole ratex exercise was indeed to make economists think more seriously about how expectations operate and influence things, even if the ratex folks themselves were hopelessly off. As for the death of monetarism, it is true that it was abandoned as a policy in the US in August 1982 when the Mexicans threatened to default and the fear of the New York money center bankers (transmitted through New York Fed President Corrigan to Volcker) overcame their love of its (successful) anti-inflationary, worker depressing aspect. Face it, Volcker's monetarism was very successful at what it was intended to achieve. But the pain got too great and scary, and so it was abandoned. Reagan agreed to dump his last round of tax cuts and Volcker agreed to cut interest rates (and dump monetarism as an active policy). That was the beginning of the long boom of the US stock market, the DJIA being in the 700s in August, 1982. But economists did not more seriously abandon monetarism until later in the 1980s. It was not in the 1970s that the velocity of money destabilized. The reasonable stability of the velocity of M1 was a major support for monetarism all through the 1950s, 1960s, and the 1970s. It was after Volcker had already changed policy, and major institutional changes began to occur in US banking, that in the mid-1980s the velocity of M1 went wacko and began bouncing all over kingdom come. This did not require any sophisticated econometrics at all to observe. One could see it with good old Doug Henwood-type eyeballing. And the Fed FOMC did exactly that and stopped paying much attention to M1 and still does not (although M2 is another thing altogether). Barkley Rosser