Quote from dhpar:
I will disappoint you - it is something I simply remember from university years which is very long time ago. Pick any book on microeconomics and look for Paasche/Laspeyres indices and impact on budget constraint for an agent.
In general price indices (CPI/PPI) are based on "optimal" baskets and are (infrequently) adjusted. GDP deflator is based on actually produced basket of goods, i.e. it is not as subjective as CPI/PPI. I tried Wiki and here is what it says: http://en.wikipedia.org/wiki/GDP_deflator (look at Calculation section)
Thanks for the explanation. I did not disappoint!

-B.
