By the TV Guide Editors in 1984, to be a Hit show for ABC in the 1984 Tv Guide fall preview. They defintely called it

Some trivia: Who's the Boss? actually got off to a slow start in the Thursdays-at-8:30 timeslot at the beginning of the 1984-85 season, against The Cosby Show and Family Ties on NBC, and Magnum P.I. on CBS. After just two episodes and extremely low ratings, ABC Network moved WTB to Tuesdays at 8:30 starting in late October, where its ratings improved.

Ratings for the first four episodes of Who's the Boss?:
1. 13.7/22 - 39th
2. 10.7/17 - 60th
3. 18.3/27 - 21st
4. 14.5/22 - 40th