The leadoff voting states of Iowa and New Hampshire are well known for their clout in the presidential race. But exactly how big is their influence? A study released today by Brown University economists said the two states each wield up to 20 times the influence of other states in selecting candidates.

Brown said the study uses statistical model to examine how daily polling data responds to returns from presidential primaries. “Evidence that early voters have a disproportionate influence over the selection of candidates violates ‘one person-one vote’ – a democratic ideal on which our nation is based,” said Brian Knight, associate professor of economics and public policy at Brown.

“The implications go even further, since populations of states such as Iowa and New Hampshire are not exactly representative of the nation in terms of diversity,” he said. Political scientists have argued while Iowa and New Hampshire may not have the same demographic mix as the rest of the country, the states reflect the critical swing voters who have helped decide the last few U.S. elections.

The study said the primary calendar was starting to resemble a “simultaneous primary” with 23 states voting on Feb. 5, which the economists said could make for a tight race. Iowa’s caucus on Jan. 3 opens the state-by-state battle to choose candidates for the November 2008 general election. It is followed five days later by New Hampshire’s first-in-the-nation primary on Jan. 8.