[discodonkey]

It seems to be using the CPI. The basket of goods & services the CPI is referencing is determined by the extensive Consumer Expenditure Survey, and reflects to a fair degree the actual spending habits of Americans.

Obviously, if you give more weight to housing, you're going to get different results. But it would distort the actual change in expenditure.

[xracy]

Why wouldn't you include housing? It's often people's largest expense?

[renewiltord]

What makes you believe that housing is not included? Consider using a search engine (Google is pretty good) and using keywords like "cpi shelter weight" or "cpi housing weight". The BLS has a page on the subject.