PhD conferral Dhr.drs. Jasper Trietsch, MSc. 21 October 2016 12:00 Supervisors: Prof.dr. G.D.E.M. van der Weijden, Prof.dr. J.F.M. Metsemakers, Prof.dr.mr. R.P.G. Grol “Implementation of local quality improvement collaboratives to improve test ordering and prescribing performance of general practitioners”