FROM THE BEGINNING OF FISCAL YEAR 1973 TO THE END OF FISCAL 1978, A NET TOTAL OF 2,381 NEW FELON BEDS HAVE BEEN FILLED IN VIRGINIA PRISONS. ANALYSIS OF SENTENCING TRENDS DEMONSTRATES THAT LESS THAN 7 PERCENT OF THE POPULATION INCREASE IS DUE TO FELONS COMMITTED WITH SENTENCES OF FIVE YEARS OR LESS. THE GREATEST IMPACT ON THE INMATE POPULATION HAS COME FROM FELONS COMMITTED WITH SENTENCES OF 15 YEARS OR MORE, WITH OVER HALF OF THE POPULATION INCREASE ATTRIBUTED TO THIS GROUP. THE FELON INMATE POPULATION IS RISING NOT ONLY BECAUSE THE NUMBER OF COMMITMENTS IS INCREASING, BUT ALSO BECAUSE THE INMATES WITH LONG SENTENCES WHO ARE ELIGIBLE FOR RELEASE IS A MUCH SMALLER NUMBER THAN THOSE COMMITTED WITH THE SAME SENTENCES BUT WITHOUT ELIGIBILITY. ALTHOUGH IT IS NOT POSSIBLE FROM THE ANALYSIS TO DETERMINE THE PROPORTION OF THE POPULATION INCREASE DUE TO AN INCREASE IN COMMITMENTS OR A DECREASE IN RELEASES, IT CAN BE DETERMINED THAT THE POPULATION WILL CONTINUE TO INCREASE EVEN IF THE NUMBER OF NEW COMMITMENTS IS SUBSTANTIALLY REDUCED. FACTORS SUCH AS CRIME-PRONE-AGE-GROUP AND POLICE ARREST RATES AFFECT COMMITMENTS BUT DO NOT AFFECT THE NUMBER OF CONFINED FELONS ELIGIBLE FOR RELEASE. TABULAR DATA ARE PROVIDED. (AUTHOR ABSTRACT MODIFIED---RCB)