(CNN) Monmouth University's poll showing a three-way tie between former Vice President Joe Biden, Massachusetts Sen. Elizabeth Warren and Vermont Sen. Bernie Sanders atop the 2020 Democratic field for president was an outlier, the university's polling director said Wednesday.

"[I]t is clear that the Monmouth University Poll published Monday is an outlier," polling director Patrick Murray said in a statement. "I understood when we released our poll that the picture it painted diverged from others."

Murray's statement came after the release of other polls showed Biden ahead of Sanders and Warren, usually by double digits -- a trend that has remained steady throughout the Democratic primary race. Many speculated that Monmouth might be an outlier, given no hugely notable events had occurred that would've changed the race substantially.

Murray defended Monmouth's polling process, citing that polls are released within 95% certainty that the results are within the margin of error, but that sometimes, polls fall outside that confidence interval and show results that diverge from the normal spread.

The director said that Monmouth didn't do anything differently than its normal methodology.

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