THE DECISION of a judge to sentence a Prince William County woman to just five years in prison for the felony murder of a 23-month-old boy in her care brought an angry reaction. Family and friends of the dead child gasped when the sentence was announced in court last week; people expressed their outrage in calls to the court and on social media.

In sentencing Jessica Fraraccio to a fraction of the 40 to 50 years sought by prosecutors, Judge J. Howe Brown anticipated the response. “The sentence that I’m going to give is not going to satisfy probably anybody, and people may talk about it for a long time,” he said. He also required the 22-year-old babysitter, following her release, to send a check of at least a dollar to a charity of her choosing every year on the anniversary of Elijah Nealey’s death. “Nothing I can do to punish her is more important than her memory of what she did.” Ms. Fraraccio admitted to causing the boy to hit his head on the floor, a table and other objects and then covering his mouth and nose with her hand, suffocating him.

Is the short sentence anomalous? Some child advocates say it is not — that the criminal justice system regularly, and wrongly, treats deaths involving child abuse or neglect more leniently than those of adults.

There has not been a systematic national evaluation of the issue, and sentencing practices vary among states. But according to Victor Vieth of the National Child Protection Training Center, prosecutors often lament that judges and juries treat deaths caused by child abuse or neglect less severely than they treat adult homicides. The Denver Post in 2012 analyzed five years of Colorado sentencing data and found that those convicted of child abuse resulting in death got prison sentences that were 25 percent shorter than those who were sentenced on comparable felony charges for deaths involving adults.

Among the factors cited in the newspaper’s investigation was the difficulty of prosecuting cases in which medical testimony may be confusing. Identifying who is responsible can also be a challenge, since children are often in the care of multiple people. Another dynamic may be judges and juries identifying with a parent or caregiver who in a moment of irrationality or frustration does something terrible. “There but for the grace of God,” is how Mr. Vieth characterized the reaction of judges and juries who know what it is like get frustrated with a child and lose their temper.

Sentences are meant to punish and to deter. The Commission to Eliminate Child Abuse and Neglect, created by Congress in 2012, is soon set to hold its first meeting. Among the issues it should examine are how crimes against children are prosecuted and adjudicated and whether the right message is being sent about the value of children’s lives.