This article concludes that methodological problems and imprecision about the concept of sentencing disparity undermine Judge Heaney's statistical case. For both reasons, his claim that sentencing disparity is worse under the guidelines is not substantiated. Further, the absence of proof that the guidelines have failed does not amount to proof that guidelines have succeeded; the extent of unwarranted disparities under the guidelines remains uncertain. Interview data and other qualitative sources suggest that sentencing problems in drug cases are acute, but difficulties in this area are distinctive and do not imply general flaws in the concept of guidelines. The most serious difficulty in drug cases, and to a lesser extent in other cases, is not disparity, but excessive uniformity. Excessive uniformity is largely a product of mandatory minimums and appellate decisions that improperly restrict the departure power. Change in these areas, along with elaboration of guidelines that permit more consideration of offender characteristics and rehabilitative needs, would add the flexibility that the Federal sentencing process needs to function effectively and provide the individualization of sentences anticipated under the Sentencing Reform Act. For Judge Heaney's analysis of the Federal sentencing guidelines, see NCJ-140530. 127 footnotes