In response to questions following a speech to the National Economists Club, Lacker said it is “tempting” for policymakers to wait until there is a “fair amount” of certainty on the economy before raising rates. However, it is easy to make the “mistake” of waiting too long, Lacker added.Note that Lacker isn't a voting member of the FOMC this year, and he frequently dissented (preferring higher rates) in 2006.
Here is Lacker's speech: The Economic Outlook.