It's interesting if you compare Tatum's rookie season to Davis' it is very compatible. They were both 19 years old and their per 36 min comparison:
Tatum: 16.4 PPG, 5.2 TRB, 1.9 AST, 1.2 STL, 0.9 BLK, 1.7 TOV, .475 FG%, .826 FT%, .434 3P%
Davis: 16.9 PPG, 10.2 TRB, 1.2 AST, 1.5 STL, 2.2 BLK, 1.7 TOV, .516 FG%, .751 FT%, .000 3P%
You could even say Tatum's per 36 was diminished being on a contender rather than a lottery team.
Full statistical comparison:
http://bkref.com/tiny/DAA8q