The parole board then sets the actual date of prison release, as well as the rules that the parolee must follow when released. During a long sentence, an offender can take full advantage of the programs that the prison has, including rehab for drug abuse or alcohol abuse, anger management, mental health, and so on, so when the offender completes the rehab or program he may be released upon request from authorities with a lower risk of recidivism. This process tries to combat the tendency of prisoners leaving incarceration after a long sentence to go back to offending in short order, without any attempt at correcting their ways. Those given short sentences usually serve the full-time (do "day-for-day") as imposed by the judge, or might receive time off for good behavior, based on state or local rules and regulations. In the mid-1970s, most state and federal prisons moved from long term to short term sentencing. Over time, though, state and federal authorities have gradually migrated their philosophies back toward long-term sentences. Many states use a mixture of the two; e.g., some offenders may receive sentences reduced by several months due to rehabilitation, counseling, and other programs, as well as good time. Since the 1840s, many jurisdictions, including the federal courts, have adopted a practice of having a probation officer prepare a presentence investigation report to inform the court as to the defendant's characteristics, including his criminal record, if any. In the 1970s, the length of incarceration had increased in response to the rising of crime rates in the United States. By the 1980s, state legislatures began to reduce judicial discretion in sentencing terms and conditions. This was especially true in cases of life imprisonment, which between 1992 and 2003 increased by 83% due to the implementation of three strikes laws. Short term sentencing, mandatory minimums, and guideline-based sentencing began to remove the human element from sentencing. They also required the judge to consider the severity of a crime in determining the length of an offender's sentence. The United States does not have a specific guideline to sentencing murderers, including serial killers. When a killer is apprehended, he will be charged with murder, and if convicted can get life in prison or receive the death penalty, depending on in which state the murders took place. Generally speaking, each victim of a murder will merit a separate charge of murder against the offender, and as such, the killer could get a life sentence, a death sentence, or some other determinate or indeterminate sentence based upon the number of murders, the evidence presented, and any aggravating or mitigating circumstances present.