The data comes from the Federally mandated campaign finance reports. See http://www.fec.gov/disclosure.shtml http://www.fec.gov/disclosure.shtml So the data co

The data comes from the Federally mandated campaign finance reports. See http://www.fec.gov/disclosure.shtml http://www.fec.gov/disclosure.shtml So the data comes from the candidates themselves and the data is heavily scrutinized for accuracy.