Hi, Cathy! What datasets are you working on in particular?
I know @jodiefm, @gdp22 , and others have discussed studying progression with regard to PPMI data: Using PPMI to study long term PD progression - #6 by jodiefm.
And @ehutchins has done pretty extensive work on harmonizing data in AMP PD (maybe @vdardov too?) Accessing Data: LONI vs AMP PD.
Good to have you here!