By Lawrence A. Greenfeld

BJS Statistician 

Since the mid-1970's, legislatures around the Nation have

sought to reduce discretion in both the sentencing process

and the determination of when the conditions of a sentence

have been satisfied. Determinate sentencing, use of mandatory minimums, and guidelines-based sentencing are illustrations of approaches that limit discretion and increase

the predictability of penalties.

A majority of State prisoners today serve presumptive sentences  90% of State inmates can estimate their probable release date, and their discharge from prison is less

likely than in the past to be determined by a parole board

decision. In 1977, 72% of those released from State prisons had served an indeterminate sentence, and a parole

board decided their release. In 1992, by contrast, less than

40% of prison releases were determined by a parole board.

Interest in truth-in-sentencing reflects continued attention 

to discretion and to the relation between sentences and

time served. Truth-in-sentencing is generally meant 

to describe a close correspondence between the sentence

imposed upon those sent to prison and the time actually

served prior to prison release. 

Data collected from States by the Bureau of Justice Statistics (BJS) indicate that violent offenders released from

State prisons in 1992 served 48% of the sentence they had

received  an average of 43 months in confinement, both

jail and prison, on an average sentence of 89 months. The

finding that just under half the sentence will be served in

confinement was confirmed through analysis of self-reports

of a national sample of State prisoners. An examination of

prison release practices for violent offenders in 31 States

reveals wide disparity across the States in sentence length

but substantially less disparity and greater consensus on

the duration of time spent in confinement. 

These findings are drawn from BJS data collection programs, including the annual National Corrections Reporting

Program (NCRP) and the 1991 sample survey of State

prisoners. (See Sources of data, page 3.)

Admissions, releases, and prisoners present

Prison releases

Participating NCRP States, representing about 8 out of 10

violent offenders released from prisons nationwide in 1992,

provided sufficient information to examine the relationship

between the sentence received and time served prior to

first release. 

Bureau of Justice Statistics

Selected Findings Number 4

U.S. Department of Justice

Office of Justice Programs

Prison Sentences and

Time Served for Violence

Violent offenders are persons convicted of homicide, kidnaping,

forcible rape, sexual assault, robbery, assault, or other crimes

involving the threat or imposition of harm upon the victim, including extortion, intimidation, reckless endangerment, hit-andrun driving with injury, or child abuse.

April 1995, NCJ-153858

Released violent offenders in 1992 served 

48% of their sentence

Type of offense Averagesentence

Average

time

served*

Percent of

sentence

served

All violent 89 months 43 months 48%

Homicide 149 71 48

Rape 117 65 56

Kidnaping 104 52 50

Robbery 95 44 46

Sexual assault 72 35 49

Assault 61 29 48

Other 60 28 47

*Includes jail credit and prison time.
Little variability was found in the percentage of sentence

served for different types of violent crimes. For most violent crimes, offenders served just under half of the sentence imposed. Those convicted of rape were found to

serve the highest percentage of their sentences, 56%. 

During the most recent 5-year period, data for released violent offenders indicated that the percentage of their sentence spent in prison remained relatively stable.

Prison admissions

Another measure of the time served relative to a sentence

is derived from those admitted to prison. NCRP obtains 

estimates of the minimum time to be served by those 

admitted to State prisons. From 1988 to 1992, sentences

received and preliminary estimates of length of stay for 

violent offenders admitted to State prisons have shown 

a consistent percentage of the sentence to be served:

Admissions in 1992 had average sentences of 104 months,

and correctional authorities predicted that they would stay

for 60% of that time. Releases that same year had average

sentences that were 15 months shorter and their length of

stay was 19 months less; releases served 48% of the sentences they received. 

Estimated percentage of sentence served or to be served 

by admitted, current, and released prisoners

Prisoner self-reports and records obtained for those released from prison tell a similar story  just under half the

sentence received will be served in confinement. Estimates

for admissions, however, may differ from the other estimates for two reasons: admissions reflect current policies

and legislation affecting the use of prison, and less is

known at admission about how long inmates will actually

serve. During the course of a prison stay, various credits

against a sentence may be earned (such as good time) or

reductions in sentence length may occur (such as sentence

rollbacks in crowding emergencies), changing the percentage of sentence actually served.

Estimating hypothetical impacts of changing 

the percentage of sentence served

Thinking about truth-in-sentencing requires at least the

knowledge of two numbers  sentence length and the actual or predicted length of stay. Since the desired goal of

truth-in-sentencing is to increase the percentage of sentence served over current practice, it is possible to estimate

what sentences and what time served would be necessary

to achieve increased correspondence between the two.

Such estimates would, of course, be speculative because

policies or practices implemented by jurisdictions seeking 

to change the percentage of sentence served may simultaneously modify both sentence length and time served.

If the current average sentence remained the same for violent offenders and a policy were adopted requiring that 85%

of the current sentence should be served, the predicted

time served would increase the current length of stay 

 for admissions, 26 months

 for prisoners present, 84 months

 for releases, an average 33 months longer in prison. 

Prison releases

Years Averagesentence

Average

time served

Percent of

sentence

served

1988 95 months 41 months 43%

1989 91 42 46

1990 94 44 47

1991 92 44 48

1992 89 43 48

Prison admissions

Years Averagesentence Average timeto be served

Percent of

sentence to

be served

1988 113 months 66 months 58%

1989 107 65 61

1990 105 63 60

1991 105 64 61

1992 104 62 60

2

Prisoner status Averagesentence Averagetime served

Percent of

sentence 

Admissions, 1992 104 months 62 months 60%

Prisoners, 1991 216 100 46

Releases, 1992 89 43 48

Based upon current sentences, what would time

served in prison be if violent offenders served higher

percentages of the sentences they had received? 

Estimated time to serve

Percent of 

sentence served

 Prison

 admissions

 Prisoners 

 present

 Prison

 releases

Current 62 months 100 months 43 months

65% 68 140 58

70% 73 151 62

75% 78 162 67

80% 83 173 71

85% 88 184 76

90% 94 194 80

95% 99 205 85

100% 104 216 89
An alternate approach would be to hold constant the current average lengths of stay and change sentence lengths,

attempting to ensure a particular ratio of time served to

sentence. As shown above, by setting the sentence as

85% of the current time served, estimated sentence lengths

would decrease  

 for admissions, 31 months

 for prisoners present, 98 months

 for releases, an average 38 months. 

How States differ in the percentage of sentence served

Among the NCRP States, released violent offenders in

1992 had an average sentence of 89 months and an average time served of 43 months; these violent prisoners had

served 48% of their sentence prior to discharge from

prison. The reporting jurisdictions can be divided into three

groups according to whether they were above, at, or below

the national average percentage of sentence served. 

About 40% of releasees were in States

that had percentages of sentence served

that were at least 10% (5 percentage points) above the national average of 48%. For these States, the average sentence was 72 months and average time served was 44

months, or 61% of the imposed sentence. 

Just under 30% of releasees were in

States that had approximately the national

ratio of time served to sentence with average sentences 

of 102 months and time served of 47 months, or 46% 

of the sentence. 

The remaining 30% of releasees were 

in States that provided release records 

in which the percent of sentence served fell at least 10% 

(5 percentage points) below the national average with sentences averaging 125 months and time served of 42

months. Discharged violent offenders in these States 

had served 34% of the sentence they had received.

These data indicate that all three groupings of States had

similar time served among violent offenders released from

prison regardless of the sentence received or the percentage of sentence served. In other words, States have a

much greater consensus on the duration of incarceration

for violent crime than could be inferred from simply examining the sentences imposed or the percentage of sentence

served.

Sources of data

In 1992, 38 States and the District of Columbia participated

in the National Corrections Reporting Program, covering

93% of State prison admissions nationwide (431,000 records) and 86% of State prison releases (348,000 records).

While the length of the sentence received was gathered 

for both groups of prisoners, time served (including jail

credits) was only obtainable for those released from prison.

For those admitted to prisons in 1992, States provided a

prediction of the expected minimum time to be served. 

In 1991 BJS conducted a representative sample survey of

State prisoners and obtained estimates from prisoners of

the likely time to be served. Approximately 14,000 inmate

interviews were conducted in 45 States.

The categorization of violent offenses is the same for both 

the NCRP and the survey of State prisoners. Beginning in

1982, a three-digit offense coding system was devised by

BJS, in consultation with State departments of corrections, 

to provide a uniform approach. A user's guide provided to

the States indicated how BJS categorized particular

offenses. 

NCRP datasets, available for public use through the National Archive of Criminal Justice Data, preserve the original

source offense codes as well as the assigned BJS offense

codes. BJS has expanded its codes over the years to take

into account groups of offenses entering common use and

to provide increased detail on other offenses. These revisions have been provided to the participating States.

Most analyses in this report used data on sentence length,

jail credits, and time served in prison from published BJS

reports. The analysis comparing States on the percent 

of sentence served used individual-level records supplied

by the States. Differences in the methods used may introduce small differences in the estimates. 

3 

Based upon current time served in prison, what would

sentences need to be to achieve higher percentages 

of sentence served? 

Estimated sentence

Percent of 

sentence served

Prison

admissions

Prisoners

present

Prison

releases

Current 104 months 216 months 89 months

65% 95 154 66

70% 89 143 61

75% 83 133 57

80% 78 125 54

85% 73 118 51

90% 69 111 48

95% 65 105 45

100% 62 100 43

Prison releases

States with a

percent of sentence served 

Average

sentence

Average time

served

Percent of

sentence

served

Above average 72 months 44 months 61%

Average 102 47 46

Below average 125 42 34

Above average

Average

Below average