Steve Williamson's Macroeconomics

I have to admit that this indeed is a fabulous undergraduate macro text. As claimed it does reflect the current practice of macroeconomics or at least the most influential one. However, the following is worthwhile to note:

1. The most common example given by almost all advocates of RBC theory of business cycles of a shock to total productivity, the oil price shock of 1970, is also present in this book. While it is true that with an exception of one, all the recessions in US have been preceded by a sharp rise in energy prices, this should work as a change in relative price of an input and hence a movement along the production function and not as a shift in it. However, even if we accept that the increase in energy prices does work as a productivity shock we cannot ignore the fact that most of the empirical studies place the contribution of energy prices to business cycles between 8 t 18 %, which is not a very significant, let alone a major one! ( Stadler 1994). This is not withstanding the fact that for technology shocks themselves to contribute to cycles, they should contribute at laest 78% to the shocks according to Aiyagari (1994).
2. I still have difficult time understanding why various authors motivate the study of endogenous growth by mentioning the failure of Solow model's prediction about convergence of growth rates across countries, but failing to mention that Robert Solow himself never intended his model to be used in that way, Easterly (2001, pp.55). Solow wrote his model on the backdrop of what is called as capital fundamentalism, a belief which postulates economic growth as a function of availability of machines per worker. He intended to show that this belief is wrong and hence capital accumulation does not cause growth in Solow model but some exogenous factor called technology does. The insight comes from the simple yet powerful logic of diminishing returns to a factor. When applied to cross country comparison of growth rates, economists extended the logic of the Solow model by assuming that, at least in principle, all countries have access to the same technology. Then, the only reason that countries, for example the tropics, did not catch up with the developed countries was lack of capital. But again the problem with this conclusion is that capital is not a very sizable factor in production. Therefore, if one wants to explain the differences in growth rates on the basis of availability of capital, then the conclusions are obviously absurd. As per the calculations of Lucas mentioned in Easterly (2001), each US worker for e.g. will have to have 900 times more machines than each Indian worker in order to explain the differences in their standard of living and thats clearly not the case.
   

All said and done, this book does a good job in presenting macro in a much clean and consistent way and avoids giving the feeling to the reader which, I got as an undergrad, that macro is a series of disconnected models with no relation to the micro behavior.


References:

Aiyagari R S (1994), On the Contribution of Technology Shocks to Business Cycles, Federal Reserve Bank of Minneapolis Quarterly Review, Vol. 18, No.1, pp.22-34.

Easterly William (2001), The Elusive Quest for Growth, The MIT Press.

Stadler George W (1994), Real Business Cycles, Journal of Economic Literature, Vol. XXXII, pp. 1750-1783.

Williamson Stephen D (2007), Macroeconomics, Third Edition, Pearson.

S. Rao Aiyagari

This guy did some exciting work in incomplete markets among host of other issues. Unfortunately, he died very early. This is a write up by Neil Wallace on him which appeared in the Federal Reserve Bank of Minneapolis Review. It also lists most of the work done by Rao. You can also find his work here.