Why are voters changing their party affiliation this election cycle?

Last Updated Mar 15, 2016 11:47 AM EDT

Since the beginning of the year, nearing 50,000 registered Democrats in Pennsylvania have switched to the Republican Party and as many as 20,000 Democrats in Massachusetts have made the same move in their state.

Several recent reports have highlighted these party affiliation switches in key states, with some suggesting that Donald Trump is responsible for driving this exodus. The GOP presidential frontrunner often claims that his campaign has attracted tons of Democrats and independent voters, but are people leaving their parties in droves because they approve of his policy positions?

"It's unclear whether voters are switching parties to vote sincerely or to vote strategically, but we do see evidence that they're switching," said Costas Panagopoulos, a professor at Yale University this year, who also teaches at Fordham University, and studies voter behavior.

Because many Democrats might view Hillary Clinton as their likely nominee, he said they might choose to vote strategically to choose the weakest GOP opponent for her to face in the general election. It's also possible voters are making the switch because they do find Trump, or what they see in the Republican race, more appealing.

"It's unclear whether people are voting for Donald Trump because they want to vote for Donald Trump, or they're voting for Donald Trump because he would be a weaker candidate against the Democratic nominee," Panagopoulos added.

Another explanation for at least part of the high numbers changing parties in is that in some states it's much easier to do so now. Since late August, voters have been able to register online. Massachusetts, too allows online registration.

Pennsylvania, which holds its party primaries on April 26, has already seen pretty hefty shifts since the beginning of the year, according to its department of state. Based on data that is updated weekly, nearly 50,000 Democrats in the state have switched to the Republican Party and more than 25,000 Republicans have switched to being Democrats. As for independents, nearly 32,000 of them have registered as Democrats and nearly 25,000 independents have registered as Republicans.

Voters in Massachusetts, who already voted in their primaries on March 1, have also changed their registration. A spokesman for the department of state told CBS News as many as 20,000 Democrats in the state have left the party this year. When asked for statistics on the numbers of Republicans or independents who have changed their affiliations, the spokesman said his office does not have such data.

Between Feb. 2 and March 4 in Nevada, which held both parties' caucuses last month, 2,451 Democrats switched to the Republican Party and 1,538 Republicans registered as Democrats, a spokeswoman for the secretary of state's office told CBS News.

Another report that has surfaced found that 1,000 blue-collar Democrats in Ohio's Mahoning County have switched to being Republicans. A spokesman, however, for the department of state said Ohio won't have updated statistics on party affiliation changes until after the results come in from the state's winner-take-all primary on Tuesday.

While it's difficult to pin down why this is happening in this election cycle, a pair of Trump supporters are making an effort to try to recruit Democrats.

Lynnette Hardaway and Rochelle Richardson, sisters from North Carolina, have launched an effort online called "Ditch and Switch" that instructs Democrats how to change their party affiliation to the Republican Party in order to vote for Trump.

"DITCH the Democrat Party and SWITCH to Republican Party to vote for Mr. Donald J. Trump in the primaries," it says on their website. "Look below to see if your state is a Closed or Open primary voting states."

The sisters, who are also known as Diamond and Silk, are urging voters to switch to the GOP in states that hold closed primaries in which only voters registered in a party can vote in that party's primary.

Changes in party affiliation have occurred in previous presidential elections, Panagopoulos said, and it usually happens when a contest is a foregone conclusion, like in 2012, when President Obama was running for a second term.

"But I don't think we've seen it happen to the degree that it has in this particular election cycle," he said.

  • Rebecca Shabad

    Rebecca Shabad is a video reporter for CBS News Digital.