After weeks of witnessing low approval ratings, President Donald Trump had reason to cheer Monday after Rasmussen Reports claimed that Trump's approval rating is at 50 percent. Trump also retweeted a post by Matt Drudge of the Drudge Report linking to the Rasmussen Reports.

It's the first time that Trump's approval rating has been at 50 percent in almost a month, according to Rasmussen Reports. It also said that 30 percent "Strongly Approve" of the way Trump is performing and 39 percent "Strongly Disapprove" of the same.

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Meanwhile, a new Gallup poll released Monday showed that only 45 percent of Americans think Trump keeps his promises — the figure declined by 17 points from 62 percent in February. However, questions arise whether the approval ratings polls are unbiased, especially after the election polls in most states failed in November, underestimating Trump's performance on the Election Day, according to the Washington Post.

Polls have been a matter of debate since Trump took office. Traditional phone polls that use live interviewers report limited support for Trump, however, automated phone and internet-based surveys show higher approval ratings for Trump, perhaps because of the element of anonymity.

The White House has questioned whether pollsters are accurately measuring Trump's popularity, according to Politico. At a White House press conference Feb. 3, when Press Secretary Sean Spicer was asked to comment on a newly released CBS News poll — conducted by live interviewers — which put Trump’s approval rating at only 40 percent, he said: "I think there’s also a Rasmussen poll that showed he had a 51-percent approval rating."

According to a new Pew Research Center survey released Monday, Trump's approval rating is at 39 percent — precisely the same as two months ago. The percentage of Americans who disapprove of Trump is almost unchanged at 54 percent, compared to 56 percent in February.

According to FiveThirtyEight — a website that focuses on opinion poll analysis — polls conducted with live-telephone interviewers, such as Gallup, show worse numbers for Trump compared to polls conducted online or by automated telephone calls. One possible theory about this difference is that the online and automated polls reveal the "shy" or "hidden" Trump support as people can maintain anonymity.