Does this sentence make sense? If not, how can it be improved?
Solution 1:
The passive voice here is clunky, although changing "...has been" to "researchers have..." is a bit of a cop-out.
I might try:
There is no consensus yet on whether studying individually is more effective than studying within a group.
Or:
Researchers have not yet reached [a] consensus on whether studying individually is more effective than studying within a group.