What are c statistics

C-statistic gives the probability a randomly selected patient who experienced an event (e.g. a disease or condition) had a higher risk score than a patient who had not experienced the event.

Obviously there are people with low scores that still have events and people with high scores that never have events but the goal is the decision score gives us an idea of who is most likely.

·       The idea or educated estimate can be turned into a C score-  and c scores are kind of like grades== a score of 1 is absolue perfect model it means the model perfectly predicts those group members who will experience a certain outcome and those who will not.

·       But we know in medicine that isn’t possible

IF

·       A value of 0.5 means that the model is no better than predicting an outcome than random chance.

·       Values over 0.7 indicate a good model.

·       Values over 0.8 indicate a strong model.