Final answer:
Increasing the proportion of people sent to prison produces diminishing returns in crime reduction and there is a limit to prison capacities.
Step-by-step explanation:
Studies have indicated that increasing the proportion of people sent to prison produces diminishing returns in crime reduction. This means that while initially, sending more people to prison may result in a significant decrease in crime, the benefits of each additional person in prison decrease over time. This is known as the law of diminishing returns. In addition to the diminishing returns, there is a limit to prison capacities, which means that there is a practical limit to how many people can be incarcerated.