ProPublica analyzed expenditure data relating to leadership PACs during the 2008 election cycle. The data, provided by the Center for Responsive Politics, includes some 67,000 transaction records connected to about 400 leadership PACs and paid out to more than 9,000 recipients.

To look at trends in the data and to compare PACs, ProPublica put each expenditure into one of 10 categories, including contributions, entertainment and administrative costs.

The descriptions were sometimes vague, so we weren’t able to classify 585 transactions totaling $966,540. Those expenditures are classified as miscellaneous.  There also are some cases where expenditure descriptions would have placed an expenditure in multiple categories – in those instances, we examined the recipient and other information to determine how to classify it.

Some of the leadership PACs are affiliated with officials who are no longer in Congress, as in the case of now Secretary of State Hillary Clinton, or have never been in Congress, as in the case of Rudolph Giuliani.

For more information about any leadership PAC, you can search documents filed with the Federal Election Commission.