This is another exceptional stuff from this super economist and one of the best guys to explain thinngs so easily. Infact, the team in Federal Reserve is simply superb in explaining things. Be it Bernanke, Krozner, Kohn all excel in explaning complex areas.
This time it is Mishkin on his favourite topic Inflation. The paper is here .Why don’t we have such explanations in India? I mean leave the empirical part, atleast we should have some understanding of the inflation process in India. If it is there I am not aware of it. I really don’t have words for NBER which keeps bringing so many thoughts (in form of academic papers) from the leading thinkers to people like me and all for free.
Anyways now to the paper. The abstract says:
This paper first outlines the key stylized facts about changes in inflation dynamics in recent years: 1) inflation persistence has declined, 2) the Phillips curve has flattened, and 3) inflation has become less responsive to other shocks. These changes in inflation dynamics are interpreted as resulting from an anchoring of inflation expectations as a result of better monetary policy. The paper then goes on to draw implications for monetary policy from this interpretation, as well as implications for inflation forecasts.
I loved this on inflation persistence:
Specifically, we need to know whether inflation tends to revert quickly to its initial level, or whether the effects of the shock persist–that is, lead to a changed level of inflation for an extended period.
The most obvious way of measuring inflation persistence is to regress inflation on several of its own lags and then calculate the sum of the coefficients on lagged inflation. If the sum of the coefficients is close to 1.0, then shocks to inflation have longlived effects on inflation. In other words, inflation behaves like a random walk, so that when inflation goes up, it stays up. If the sum of the coefficients drops well below 1.0, then a shock to inflation has only a temporary effect on inflation, and inflation soon reverts back to its trend level.
The evidence for US is:
In particular, when autoregressions are run using rolling samples with a fixed width of, say, twelve years, the sum of the lagged coefficients often falls noticeably below unity as the sample advances to include the most recent data.
He further illustrates a model used in another paper:
Recent work by Jim Stock and Mark Watson (2007) provides an alternative and, to me, a quite intuitive way of thinking about inflation persistence. They estimate a model that decomposes inflation into two components. The first component, which can be thought of as the underlying trend, follows a random walk, so that shocks to this component persist indefinitely and thus affect the trend inflation rate going forward. The second component is a serially uncorrelated shock, meaning that such shocks are temporary and lead to only transitory fluctuations around the trend.
He then goes on to defend the fact that inflation expectations are very important and it is anchoring of the same which is crucial for any policymaker. Basically in a paper by a super team, it was pointed out that the role of inflation expectations is not as much as we think it to be. This wasn’t agreed by Lacker, Kohn, Poole and now Mishkin.
Read the paper for the simplicity and the way he explains the empirical models. A good weekend read!






