Despite the hype surrounding Mitt Romney's vice presidential pick. Paul Ryan has done little to boost the Republican presidential ticket, according to the latest NBC/Wall Street Journal poll.

The poll, the first major survey released since Ryan's addition to the ticket, shows that the Barack Obama-Joe Biden ticket leads Romney-Ryan by four points among registered voters, 48% to 43%. That's only a slight change from July, when Obama led Romney 49% to 43%.

The numbers suggest that Ryan has done little — if anything — to boost Romney. Voters surveyed were split on Ryan, with 22% saying that his addition to the ticket makes them more likely to vote for the Republican presidential candidate, and 23% saying it made them less likely to vote for Romney. More than half of voters — 54% — said that Romney's V.P. pick did not affect their vote at all.

Ryan's -1 margin makes him an outlier among other recent vice presidential picks. In 2008, Joe Biden and Sarah Palin saw +8 and +9 margins, respectively; John Edwards had a +21 margin in 2008.

Ryan's favorabilty ratings are also split, with 33% of voters surveyed saying they had a favorable view of the Wisconsin Congressman, compared to 32% who said they saw Ryan unfavorably.