Final answer:
The impact of new sentencing structures and practices on crime rates is unpredictable and varies.
Step-by-step explanation:
The true statement regarding the impact of new sentencing structures and practices is Option 3: Their impact on crime rates is unpredictable and varies.
Research has shown that the impact of new sentencing structures and practices on crime rates cannot be universally predicted or generalized. Different approaches to reducing crime, such as incarceration, rehabilitation, prevention, and restorative justice, have varying degrees of effectiveness depending on the type of crime and the specific offender.
Several factors, including demographics, social changes, and individual circumstances, contribute to the unpredictability and variation in the impact of new sentencing structures and practices on crime rates