In an argumentative paragraph, which type of evidence is generally strongest for establishing causal claims?

In an argumentative paragraph, which type of evidence is generally strongest for establishing causal claims?

• A. Anecdotal evidence
• B. Expert opinion
• C. Experimental or quasi-experimental data
• D. Theoretical reasoning

Answer: (C)

When making a causal claim, the strongest evidence comes from data that actively tests whether changing a factor produces a change in an outcome while holding other variables constant. Experimental or quasi-experimental designs do this by manipulating the cause and comparing what happens to a treated group versus a control group (or using a natural experiment that approximates randomization). Random assignment helps ensure the groups are similar at the start, so differences in the outcome can be attributed to the manipulated factor rather than to preexisting differences or external influences. That control over confounding factors gives us high internal validity, which is essential for arguing that one thing truly causes another. Anecdotal evidence relies on individual stories, which may not generalize and can be biased by selective reporting. Expert opinion, while informed, reflects authority rather than empirical demonstration of causation. Theoretical reasoning can suggest a mechanism, but without data showing the effect in real-world settings, it cannot firmly establish a causal link.

When making a causal claim, the strongest evidence comes from data that actively tests whether changing a factor produces a change in an outcome while holding other variables constant. Experimental or quasi-experimental designs do this by manipulating the cause and comparing what happens to a treated group versus a control group (or using a natural experiment that approximates randomization). Random assignment helps ensure the groups are similar at the start, so differences in the outcome can be attributed to the manipulated factor rather than to preexisting differences or external influences. That control over confounding factors gives us high internal validity, which is essential for arguing that one thing truly causes another.

Anecdotal evidence relies on individual stories, which may not generalize and can be biased by selective reporting. Expert opinion, while informed, reflects authority rather than empirical demonstration of causation. Theoretical reasoning can suggest a mechanism, but without data showing the effect in real-world settings, it cannot firmly establish a causal link.