The problem is the Fed and the markets don't see eye to eye on the outlook for interest rates. The Fed forecast, last updated in June, shows it expects two hikes to the federal funds rate this year, after beginning 2016 projecting four rate increases.
It still has four for next year and the year after. Many economists expect those forecasts to slip back to just one hike for this year and some say it's more likely there will be just three increases in each of the next two years.
"The information value is low in this. They've just been proven incorrect so many times," said John Briggs, head of strategy at RBS.
The Fed is not expected to take action on rates when it winds down its two-day meeting Wednesday afternoon. But the 2 p.m. EDT statement could provide some guidance on how it sees the economy and how it feels about hiking rates later in the year. Economists mostly expect the next rate increase in December.
The central bank also will project the neutral rate, where it eventually sees the fed funds target heading. That was just above 3 percent in June, but economists now say that's a number that could drop.
"It has been coming down consistently," said Diane Swonk, CEO of DS Economics. "The Fed has consistently been lowering the terminal rate and lowering its trajectory. The markets have been more accurate than the Fed which we know, but that doesn't mean they will continue to be that way."
Swonk said she'd like to see the Fed move away from the "dot plot." "I think they add more confusion than clarity because there's such a dispersion. It's not clear how much it represents a consensus of what the Fed expects," Swonk said.
She said the Fed could leave the dots on its target for next year. "If they don't go in September, some may want to keep four for next year, and others may say, 'Hey I think we just lowered the trajectory.'"
Swonk said one official could skew the outlook, such as former Minneapolis Fed President Narayana Kocherlakota, who had a negative dot in his forecast last year. St. Louis Fed President James Bullard also impacted the dot plot when he revealed he put down only one more interest rate increase through 2018.
This is what to watch when the "dot plot" is released Wednesday. The number of Fed officials that now expect one rate hike should move higher if the central bank holds rates steady at this meeting, as expected. It has only raised rates once in the last 10 years, and the fed funds target is now at about 0.375 percent.