I obtain an estimate of b<0.

Prior researchers running the a similar regression obtain an estimate of b>0: I'm trying to reconcile this difference.

The only methodological difference driving our results is the following:

In my study, both y and x are continous variables.

The prior researcher uses ranked data: y ={1,2,3,4,5} and x={1st,2nd,..... nth}.

My question is: can the difference in methodology explain the difference in estimates for b (sign change)? If so, how?

Many thanks to anybody who comments