I number of people have asked me why I have not replied directly to Scott Sumner’s criticism of this and subsequent posts of mine, particularly as he keeps claiming that I made some mistake. Well, for the record, I do sometimes make mistakes, and when they are pointed out I acknowledge them. However on this occasion my writing on this issue seems pretty consistent to me and as far as I’m aware error free. So, why no reply?
Well, I did in fact leave a comment on Scott’s second post. Scott then wrote another post (rather than comment on my comment). I stopped at this point, partly because the subject matter appeared to be moving away from what Cochrane and Lucas said to other issues which were not obviously relevant to my original point. I think Brad DeLong nails it here. This is one of the problems with the ‘you were inconsistent here, and you have forgotten this here, but you are a professor at Oxford so I’ll give you the benefit of doubt’ sort of exchange. I think it can muddle rather than clarify an issue.
So instead I wrote a few self contained posts which tried to throw light on some of the issues, but which also made sense on their own. The original quotes I looked at appeared to suggest that if taxes went up, consumption would immediately fall by the same amount (“it’s just a wash”). I pointed out in my original post that this will not happen because of consumption smoothing. What I had not anticipated is that some people might think that lower saving would automatically lead to an equal fall in spending on capital goods without any change in income (another wash). That is why I wrote the savings equals investment post, which explained why this would not happen. Some of the comments to my original post said hey, these guys are just assuming full employment, so I wrote this on that general issue. There also seemed to be some confusion in the debate on the difference between behavioural responses and equilibrium relationships, which Paul Krugman and subsequently Brad DeLong discussed, and which Chris Dillow brilliantly anticipated. As the debate went on, I thought I could clarify a point about multipliers and consumption smoothing (or ‘Old Keynesian’ and New Keynesian models), so I wrote this. I’m glad to see that John Cochrane is now less dismissive of fiscal stimulus, which leads Noah Smith to make observations about politics and macro that have some similarities to those in my original post.
While I’m on the subject of comments, I should say something about comments on my own posts. I had not anticipated so many people reading my stuff, and therefore so many comments, and if I tried to answer them all I would have to neglect the day job. However I do read them all, and if there is a common theme that I would like to say something on, I’ll write a new post on it (like ‘Demand Denial and Ideology’). One exception is where someone points out an error in what I wrote, or something where in retrospect I think I have been misleading or unclear, in which case I think it is sensible to recognise that immediately by replying to the comment. So thank you to those who have left comments, as I do find them useful.