The last analytical type of epidemiologic study in presented on this slide.  It is called a prospective study and the goal is looking at the future outcome.  In other words, at present time we know an individual’s potential risk factors.  Therefore, the goal is to follow subjects who have been exposed and not been exposed to potential risk factors for a given period and observe the outcome of the disease.  This type of study is openly used in diabetes research.  DCCT and DPT is a few of the prospective diabetes research we have been hearing about for a long time.