What’s more, 18- to 29-year-olds continue to lag behind Americans aged 30 and older on these important turnout indicators.

As a result, 18- to 29-year-olds now constitute 12% of Gallup’s traditional likely voter sample, basically the same as the estimate in the final 2004 pre-election poll (13%). Gallup’s expanded likely voter model, which defines likely voters differently (on the basis of current voting intentions only), estimates a slightly higher proportion of young voters in the electorate (14%). However, even if the share of the youth vote were adjusted upward, doing so has little or no impact on the overall Obama-McCain horse-race numbers using either likely voter model.

It is possible that the 18- to 29-year-old share of the likely voter electorate will grow in the final days of the election. Although interest in the election and voting intentions usually increase as Election Day grows nearer, Gallup did not observe much of an increase from mid- to late October 2004, because interest was already at high levels (as it is this year).

From Gallup.