Differential turnout by gender, age, and region of the state will determine whether the state moves toward one candidate or the other. For example, respondents from Philadelphia and Southeastern Pennsylvania represent 31 percent of likely voters in the sample but 36 percent of the state's registered Democrats. Since Obama leads among these voters, turnout that is equivalent to registration in the Southeast would mean a closer race. The same is true for the youngest voters (ages 18-34), who represent only seven percent of likely voters but constitute about one-quarter of all registered Democrats.
I'm assuming that their "likely voter" model is based on traditional primary turnout patterns, which have gone out the window this year. According to CNN's
exit poll, 16% of the Democratic primary voters in Ohio were age 17-29, while another 17% were age 30-39. In
Maryland, the numbers were 14% and 17%, respectively.