The landmark study, labeled an exemplary case control study, by Joel Selby at Kaiser, showed that there was about a 60% reduction in mortality to colorectal cancer in the case control study within reach of the sigmoidoscope. Basically, they looked at people who died of distal cancer compared to match controls and they found that people who died were much less likely to have had a sigmoidoscopy and this is how they inferred this data. There is one real randomized trial that we are doing, and Dr. Weissfeld is the Principal Investigator in Pittsburgh, part of the PLCO trial, and I will show you some work that we’ve done with the PLCO cohort that leads to this.