I have not yet read all of the 55 page report, but the exercise sounds somewhat futile because many expenditures likely don't fit into any agency goals. For example, what federal agency supports not only ownership of a vacation home, but also having a mortgage on it? Does the Department of Education's goals include making sure couples with up to about $180,000 of income can get a $10,000 scholarship (American Opportunity Tax Credit) for a child? Seems to be contrary to the underfunded Pell grant program designed to help those in need pay for tuition.
The GAO website includes a nice infographic reproduced here. Too bad it is not part of any effort to increase government finance literacy among the public. I think it would be easier to broaden the tax base if more people knew of the costs of some of these tax expenditures and the minority of taxpayers who benefit from many of the more costly ones. Helpful information would include how, for example, the annual $80 billion for the mortgage interest deduction might be used more widely to help more taxpayers. [Data shows that only 1/3 of individuals itemize and that the mortgage interest deduction primarily helps higher income individuals buy a more expensive home. Also home ownership rates in the US are similar to UK and Canada that don't have this deduction (see p 27 of this JCT report.]
What do you think?