They voted in the same way something like 84% of the time.
Duh. They’re both Republicans. Any two Republicans would have a high correlation of similar votes.
During the eight years that Thompson and McCain served together, they cast votes on 102 CQ-defined key votes and agreed on 83 of them - or 81.4 percent of the time. They disagreed 18.6% of the time, that’s pretty high considering that both are Republicans and both are considered relatively conservative. Just as an example from one year, among the instances in which Thompson and McCain differed were votes in 2002 to effectively extend a repeal of the estate tax beyond 2010, to authorize oil drilling in Alaskas Arctic National Wildlife Refuge, and to postpone tougher automobile fuel efficiency standards. Thompson voted aye and McCain voted no in all three cases.
Thompson also was the lone standout in several 99-1 votes, including mandatory seat belt laws and mandated federal DUI blood alcohol levels.