Root Cause (Person of Interest)

In its original American broadcast, "Root Cause" was seen by an estimated 15.10 million household viewers and gained a 3.3/9 ratings share among adults aged 18–49, according to Nielsen Media Research.[1] This was a 4% increase in viewership from the previous episode, which was watched by 14.40 million viewers with a 3.2/8 in the 18-49 demographics.[2] With these ratings, Person of Interest was the second most watched show on CBS for the night beating The Mentalist and !Rob!, but behind The Big Bang Theory, second on its timeslot and fourth for the night in the 18-49 demographics, behind Grey's Anatomy, The Big Bang Theory, and American Idol.

"Root Cause" received generally positive reviews from critics. Keysha Couzens of TV Overmind wrote "Last night, Person of Interest was back to being the kind of show that makes it required viewing. In fact, the team behind POI delivered one of the better episodes of the season by telling the story of a family man down on his luck set up to be a patsy in a political assassination."[3]

Luke Gelineau of TV Equals wrote "Person of Interest returned this week with 'Root Cause', another solid episode that was mildly entertaining, but failed to really push the overarching story forward in any real way."[4]

Sean McKenna of TV Fanatic gave the episode a 4.8 star rating out of 5 and wrote "Person of Interest has really found its groove, combining pure fun action with a well-paced and suspenseful plot. It makes for a fantastic ride that has me looking forward to next week to see both Finch and Reese in action, simply saving the world, one POI at a time."[5]