Question

Many researchers have tried to determine whether capital punishment deters murder. Suppose a new study has been published analyzing how death-sentence rates in one year relate to murder rates the following year. The researchers who conducted this study included only the 32 states that authorize the death penalty, and excluded the remaining states. Do you think this is a justifiable approach to studying the possible deterrent effects of the death penalty? Would you trust the results of the analysis and the conclusions the researchers reach on the basis of those results? Explain your answer. These questions are related to the chapter about types of variables and levels of measurement

Answer 1

The aim of the study was to find out whether capital punishment deters murder.
The sample of the study was the 32 states that autorize the death penalty excluding the remaining states.
The variable of interest here is the deterrent effects of the death penalty.

To examine the deterrent effects of the death penalty or capital punishment, it is important to compare the states that authorize the death penalty with states who do not authorize the same. Hence, this approach to study the possible deterrent effects of the death penalty only is not a justifiable approach as we do not have a second sample to compare.
The validity of the results from the given analysis is poor as it does not determine whether not having a capital punishment improves the situation or not. Hence, we would not trust the results of the analysis.