THE ANALYSIS INDICATES THAT THE FOLLOWING VARIABLES HAVE A SIGNIFICANT EFFECT ON THE LIKELIHOOD THAT A DEFENDANT WILL RECEIVE A PRISON SENTENCE: (1) THE SEVERITY OF THE OFFENSE; (2) THE DEFENDANT'S INCOME (NEGATIVE EFFECT); (3) PRIOR ARREST RECORD; AND (4) THE STRENGTH OF THE CASE AGAINST THE DEFENDANT. THE INFLUENCE OF THE DEFENDANT'S SEX COULD NOT BE MEASURED, AND RACE, AGE, AND EMPLOYMENT WERE FOUND TO BE OF LITTLE OR NO IMPORTANCE. THE FOUR SIGNIFICANT VARIABLES HAD A GENERALLY ADDITIVE EFFECT. FURTHER ANALYSIS SHOWS THAT A DEFENDANT'S INCOME AFFECTS THE LIKELIHOOD OF GOING TO PRISON AFTER CONVICTION, BUT NOT THE LIKELIHOOD THAT A CONVICTION WILL BE OBTAINED. MOST OF THIS EFFECT CAN BE EXPLAINED BY THE LOW-INCOME DEFENDANT'S RELATIVE LACK OF OPPORTUNITY FOR PRETRIAL RELEASE AND THE GREATER LIKELIHOOD THAT HE WILL HAVE A COURT-APPOINTED RATHER THAN A PRIVATELY RETAINED ATTORNEY. THE IMPLICATION OF THIS INTERPRETATION IS THAT THE APPARENT DISADVANTAGE OF THE LOW-INCOME DEFENDANT COULD BE OVERCOME BY IMPROVING PRETRIAL RELEASE AND DEFENSE SERVICES. A DISCUSSION OF IMPLICATIONS FOR SENTENCING PROCEDURES POINTS OUT THAT, ALTHOUGH BROAD JUDICIAL DISCRETION MAY ENABLE THE DEFENDANT'S INCOME TO EXERT ITS CONSIDERABLE INFLUENCE, NARROWING OF JUDICIAL DISCRETION MAY NOT REDUCE THE EFFECT OF INCOME IF EXISTING PLEA-BARGAINING PRACTICES CONTINUE. SUPPORTING DATA AND REVIEWS OF RELATED STUDIES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED--LM)