relationship between variables

To establish a causal relationship between variables, three criteria must be met—

• covariation (where two or more phenomena vary together)
• time order (where the assumed cause precedes the assumed effect)
• non-spuriousness (where the relationship between the two variables is not explained by a third, unknown variable.)

As described in the course materials, many threats to validity exist, and if not properly controlled, research results can be erroneous. The same problems can apply to beliefs we develop through personal experience, advocacy statements presented for political reasons and not well-supported by fact, or folklore presented as common knowledge. With that in mind, please apply what you have learned in this module to the following questions.

Based on your readings, respond to the following:

• Discuss one of the following statements to reflect what you have learned about the criteria of causation and threats to the validity of causal inference.
• What cause-and-effect relationships are implied?
• What are some alternative explanations?
  1. Guns don’t kill people; people kill people.
  2. Capital punishment prevents murder.
  3. Marijuana is a gateway drug that leads to the use of other drugs.
• In describing different approaches to the time dimension, criminologist Lawrence Sherman (1995) claims that cross-sectional studies can show differences and that longitudinal studies can show change. How does this statement relate to the three criteria for inferring causation?

In 700 words and APA format (intext citation)