It scored 267.6 points on the Content Power Index, becoming the most popular TV program from May 1-7.
CPI, developed by entertainment company CJ E&M and Nielsen Korea, measures the popularity of TV shows based on the number of views of related news stories, online search tallies and buzz on social media.
In the survival audition show launched in 2016, a group of viewers called "public producers" choose by popular vote the members of a new project idol group from a pool of 101 trainees from various entertainment companies, as well as the group's roster, concept and debut song.
The show's first season featured a pool of female singers and culminated in the formation of the 11-member project girl group I.O.I. The newest season features only male trainees.
tvN's popular Saturday evening reality show "Youn's Restaurant" also held its ground in second place with 238 points, followed by MBC TV's "Rebel: Thief Who Stole The People" coming in at third with 237.9 points.
MBC TV's weekend comedy show "Infinite Challenge" climbed six notches to finish fourth, and KBS 2TV's weekday drama "Ms. Perfect," starring actress Ko So-young, ranked fifth.
"Radio Star," MBC TV's late night talk show, rose two steps to come in at sixth, and SBS TV's weekend reality TV show "Mom's Diary -- My Ugly Duckling" slid fourth pegs to seventh place. (Yonhap)