The Will Rogers phenomenon is encountered in many disciplines but is particularly relevant to radiology in the setting of staging scans and is due to reclassifying borderline individuals also known as stage migration 1.
The most common example in medicine is upstaging certain patients with malignancy by changes in criteria or technique, resulting in the worst patients in the lower stage becoming the best patients in the higher stage. The end result is that both lower and higher stage improve their outcome when viewed as separate cohorts without any individual patient or the whole patient group improving.
As a concrete example, imagine that a newer CT technique enables very small hitherto unseen pulmonary metastases to be diagnosed with certainty. As a result, a number of individuals with tiny metastases that would have been overlooked and classed as M0 (no metastases) in TNM staging now are classed as M1 (metastases present).
The M0 cohort has lost the individuals who had tiny metastases and would have done worse than those without metastases, while the M1 group gains individuals with very early metastases who will survive longer than other M1 patients with more advanced metastatic disease.
The net result is that both the M0 and M1 groups will have improved outcomes even though no individual patient has done better. In fact even if looking at the whole group (M0 + M1) the outcome will remain unchanged.
History and etymology
Will Rogers was an American comedian active during the early decades of the 20th century at the time of Great Depression. During that time a large migration of individuals from the Dust Bowl to California occurred. Will Rogers is quoted as having said "When the Okies left Oklahoma and moved to California, they raised the average intelligence level in both states."
The term Will Rogers phenomenon was first proposed by Feinstein et al in a 1985 NEJM article 2 although it remains unclear if the quote is correctly attributed to Will Rogers.
- 1. Sormani MP. The Will Rogers phenomenon: the effect of different diagnostic criteria. (2009) Journal of the neurological sciences. 287 Suppl 1: S46-9. doi:10.1016/S0022-510X(09)71300-0 - Pubmed
- 2. Feinstein AR, Sosin DM, Wells CK. The Will Rogers phenomenon. Stage migration and new diagnostic techniques as a source of misleading statistics for survival in cancer. (1985) The New England journal of medicine. 312 (25): 1604-8. doi:10.1056/NEJM198506203122504 - Pubmed