I’ve co-authored a new report on outside group political advertising in federal elections.  The report covers the elections of 2000 to 2016 (through early August of this year) and focuses on the amount of ads in presidential and congressional elections from groups that do or do not disclose their donors to the public.  The latter groups we refer to as “dark money” groups, in that their donor bases are unknown.  There are some great data in the report!