One of the most common questions pollsters have been asking for years is some version of this: "If the election was held today, which party's candidate would you vote for in your Congressional district?" (That exact wording is how CNN asks the question.) It's a broad question that shouldn't be used to determine whether one specific member of Congress will win or lose. What the generic ballot has proven useful for over the years is as a sort of national weather vane -- suggesting which way the political winds are blowing, and how hard. (Alternative take
: The generic ballot matters less than we think.)
Democrats, traditionally, have a slight edge on the generic ballot. So, if Republicans have a big margin in it or Democrats have a large -- double digit -- lead, it's usually interpreted to mean the wind is blowing strongly in one direction.