Most economists agree that frequent, clear communication and greater transparency are good things for central bankers. Whether Warsh likes it or not, markets need a message. In today's environment, a failure to communicate is simply not an option.

Federal Reserve Chairman Kevin Warsh is set to deliver his biggest speech yet on Friday, but investors may not hear what they want.

Most economists agree that frequent, clear communication and greater transparency are good things for central bankers. Whether Warsh likes it or not, markets need a message. In…