The Oklahoma actor Will Rogers said “When the Okies left Oklahoma and moved to California, they raised the average intelligence level in both states.” This statement has led to the “Will Rogers phenomenon” which, in its basic form, takes place when an increase in the average value of each of two sets is achieved by moving an element from one set to another. This leads to the conclusion that there has been an overall improvement, when in fact essentially nothing has changed. Versions of the Will Rogers phenomenon can occur in cancer epidemiology, especially when changes are made to the definition of cancer stages.
Julian Stander and his cousin Mark who is a scientist based in industry have just had a paper accepted for publication in the Biometrical Journal in which they discuss a method for correcting for the Will Rogers Phenomenon. The Standers apply their method to data from breast cancer patients and also explain how to take account of uncertainty associated with published survival rates.