William Blair analyst Brian Weinstein attributes yesterday's selloff in shares of Exact Sciences to the "ugly healthcare tape" as well as an article published last week in PLoS One that "once again" looked at cost effectiveness of various colon cancer screening methodologies. However, the article is more of an academic exercise than anything that could affect actual reimbursement or guideline inclusion, Weinstein tells investors in a research note. As such, he believes yesterday's selloff in Exact Sciences shares "is overdone as it relates to this issue." Weinstein writes, "We see nothing new that happened Monday other than a weak market taking down valuations in the sector and a misunderstanding of an academic paper by a class of uneducated investors as it relates to Exact Sciences." He keeps an Outperform rating on the shares.