It is interesting reading about pre-sentencing reports. Apparently they are used all over the place ... eg: US, Australia, UK. (According to the many links out there)
Due to the fact that judges do not have the time to investigate the intricacies of a convicted criminal's life.
They look at things like:
The underlying facts of the offense
The defendant’s health and medical and psychiatric background
Family background
Educational and employment history
Assets, income and expenses
Criminal record
Educational, treatment and rehabilitative programs available for the defendant
Sentencing guideline calculations
Sentencing recommendation
Here is one link ..
Pre-sentence Investigation Report and Interview