It'll be interesting to see who at the Fed dissents

There's a lot to watch from the Federal Reserve today.

Not only is there the big decision on whether or not to raise rates (the consensus is that they will), but there's the dot plot, the expectations for economic conditions, and Fed Chair Janet Yellen's press conference.

But, if you want to know where the Fed may be headed next, there's something else you need to watch for.

"It will be interesting to see who dissents," Stifel chief economist Lindsey Piegza told Business Insider. According to Piegza, the number of dissents and who dissents will help forecast the Fed's thinking.

The more dissents, the more likely the Fed will go incredibly slow with subsequent rate hikes.

Art Cashin, the director of floor operations for UBS Financial Services at the New York Stock Exchange, concurred with the sentiment in a note on Wednesday.

"If the Fed moves as expected, a key will be if there are dissenting votes, and, if so, how many," he said. "While Yellen likes unanimity, several dissents could underscore the no rush to hike theme."

To Piegza's other point, who makes of the dissents could also paint a picture of the future.

Dissents are not unprecedented, in fact there hasn't been a year without a dissent since 2004 according to a study by the Federal Reserve Bank of St. Louis. What would be notable is if a Governor dissented, as it would have more bearing on 2016 and beyond.

There are two types of members of the Federal Open Markets Committee, Presidents of Federal Reserve Bank Branches and Federal Reserve Governors. While 5 of the 12 Federal Reserve Branch Presidents rotate onto the Federal Open Markets Committee, the Governors are on the FOMC throughout their President-appointed, 14-year term.

"Assuming the FOMC hikes rates, we believe a dissent is likely, either by Chicago Fed President [Charles] Evans or Governor [Lael] Brainard," said UBS' economist Drew Matus in a note on Tuesday.

Bank of America economist Michael Hanson also cited Evans and Brainard as possible dissenters, but added Governor Daniel Tarullo might do so as well. Unlike Piegza, Cashin and Matus, however, cautioned in reading too much into it and pointed out that Evans is not a voting member again until 2017.

While much of the focus will be on the initial decision and Yellen's explanation, if you want to know the future it might be a good idea to see who disagrees.