PROPONENTS OF INCREASED IMPRISONMENT OF OFFENDERS FREQUENTLY ARGUE THAT INCAPACITATION REMOVES OFFENDERS, NOTABLY HABITUAL OFFENDERS, FROM THE COMMUNITY AND THUS REDUCES THE POTENTIAL FOR CRIME. WHILE IT CANNOT BE DOUBTED THAT A PERSON IN PRISON IS PREVENTED FROM COMMITING A CRIME DURING THE PERIOD OF IMPRISONMENT, THOSE ADVOCATING A DECREASE IN THE USE OF IMPRISONMENT REASON THAT THE EFFECT OF INCAPACITATION UPON THE CRIME RATE IS INSIGNIFICANT. INCAPACITATION STUDIES AIM AT RESOLVING THIS DEBATE. THE MAJOR STUDIES OF INCAPACITATION TYPICALLY YIELD CONCLUSIONS IN TERMS OF THE NUMBER OF CRIMES PREVENTED BY THE LEVEL OF CUSTODY USE PREVAILING RELATIVE TO NO CUSTODY AT ALL OR SOME ALTERNATIVE LEVEL OF THE USE OF CUSTODY. THE LOGIC OF INCAPACITATION STUDIES PLACES THOSE FAVORING DECARCERATION IN A 'NO-WIN' SITUATION. IF INCAPACITATION EFFECTS ARE FOUND TO BE SMALL, DETERRENCE EFFECTS COULD STILL BE CITED TO JUSTIFY A POLICY OF HIGH LEVELS OF INCARCERATION. IF INCAPACITATION EFFECTS ARE LARGE, THIS OF ITSELF JUSTIFIES A POLICY OF HIGH LEVELS OF INCARCERATION. THE ASSUMPTIONS UPON WHICH INCAPACITATION STUDIES ARE BASED ARE ALSO CRITICAL. DEPENDING ON THE ASSUMPTIONS MADE, THE MAGNITUDE OF THE INCAPACITATION EFFECT VARIES WITHIN AN EXTREMELY WIDE RANGE. IT IS DIFFICULT TO ENVISION LEVELS OF CLEARANCE BEING ACHIEVED WHICH WOULD NARROW THAT RANGE SUFFICIENTLY TO MAKE ESTIMATES OF INCAPACITATION EFFECTS USEFUL. IT IS THEREFORE IMPROBABLE THAT INCAPACITATION STUDIES WILL SIGNIFICANTLY ADVANCE THE UNDERSTANDING OF THE EXTENT OF PUBLIC PROTECTION AFFORDED BY IMPRISONMENT FOR THE PURPOSE OF INFLUENCING SENTENCING POLICY. REFERENCES ARE PROVIDED. (RCB)