List and discuss the three criteria for establishing causality

Question

What will be an ideal response?

Answer 1

Generally, you must meet three criteria before you can say that you have evidence for a causal relationship:
1 . Temporal precedence
2 . Covariation of the cause and effect
3 . No plausible alternative explanations

Temporal precedence is basically a fancy term for time order. To establish temporal precedence, you have to show that the cause happened before the effect.

Covariation of the cause and effect means that whenever you administer a program, you observe the outcome, but when you don't give the program, you don't observe the outcome. This provides evidence that the program (independent variable) and outcome (dependent variable) are related.

No plausible alternative explanations refers to the possibility that some other variable or factor is causing the outcome. This is sometimes referred to as the third-variable or missing-variable problem, and it's at the heart of internal validity. One alternative explanation is that it's not your program that caused the gain but some other specific, say historical, event. How do you rule this out with your research design? One of the simplest ways would be to incorporate the use of a control group—a group comparable in every way possible to your program group except that they didn't receive your program.

In most applied social research that involves interventions or evaluating programs, temporal precedence is not a difficult criterion to meet because you administer the program before you measure effects. Establishing covariation or association is also relatively simple, because you have some control over the program and can set things up so you have some people who get it and some who don't (and then you can measure what happens if there is X and conversely, if there is no X). Typically the most difficult criterion to meet is the third—ruling out alternative explanations for the observed effect. Research designs give us a mechanism that helps us rule out some of the most important alternative explanations. That is why research design is so important when it comes to causality and also why it is intimately linked to the idea of internal validity.