To determine the top donors to 2014 statewide ballot measure fights nationwide, the Center for Public Integrity collected and analyzed state campaign finance data for 85 ballot measure committees.

The Center for Public Integrity chose those ballot measure groups because they ran television ads during 2014 about statewide measures. (Five other entities, which also ran ads, did not disclose the source of their money to state or federal agencies.) Only 58 of the 158 statewide measures had TV ads, according to a Center analysis of data from media tracking service Kantar Media/CMAG, but those measures represent some of the most prominent and expensive initiatives in 2014. TV ads are typically the heftiest expense in ballot measure fights.

The Center analyzed contributions made in 2013 and 2014 to the 85 groups backing or opposing those measures, available as of Jan. 9. Such data provide a picture of the donations, but it is imperfect because some states’ final campaign finances reports had not yet been made public.