Look Placements actually depends.on lot of factors, you can't just say that if a particular institution has received high placements this year so it is better. Just like 12th batch of any coaching institutes it depends on batch of that placement year. From IIT dhanbad the first batch of iitians will pass in 2020 so we can't consider their previous placements but they have a good alumni network. IIT ropar is better in placements than iit patna in electrical not in cse. IIT patna  cse branch is better than IIT ropar. IIT patna has a good number of gsocs, as well as acm-icpc world finalists.