the states may use different ways of doing so (such as a website or a phone number). Though the Act mandates the use of provisional ballots nationwide, it exempted the six states that had been exempted from the National Voter Registration Act of 1993 because those states had and continue to have either "same-day" voter registration or no registration requirement at all: Idaho, Minnesota, New Hampshire, North Dakota, Wisconsin, and Wyoming. However, those states may choose to use provisional ballots. , North Dakota, Wisconsin, and Wyoming used them for some purposes, while the other three did not have provisional ballots at all. Potential problems In the 2018 midterm elections, both valid and invalid provisional ballots were mixed together in Florida after the initial vote count, which provided no way to be separated for the recount. Computer scientist and election official Douglas W. Jones has criticized the offer of a provisional ballot as "a way to brush off troublesome voters by letting them think they have voted." He expressed the concern that, under some states' laws, casting a provisional ballot at the wrong precinct would disenfranchise voters who could have cast valid ballots had they been redirected to the proper precinct. Academic research has suggested that provisional ballots tend to lean more toward the Democratic Party than the electorate as a whole, and that this contributes to a phenomenon, first identified by Edward Foley known as "blue shift," under which Democrats increase their share of the vote as more ballots are counted. This can potentially result in a different outcome from the one indicated by the initial count on the night of the election. Some experts on voting have suggested that this shift could be misunderstood and lead to erroneous claims of electoral fraud or corruption. Rates of acceptance According to the Election Assistance Commission thousands of provisional ballots are not counted each election. The 2004 US Presidential Election was the first presidential election conducted under the Help America Vote Act's provisions. Nationwide, at least 1.9 million provisional ballots were cast, and 676,000 were never counted due to various states' rules on counting provisional ballots. Studies of the use of provisional ballots in the 2006 general election in the United States show that around 21% of provisional ballots were rejected. About 44% of these were cast by voters who were not registered, but many other rejections were for reasons that were