Because Strengthen and Weaken questions require you to perform opposite tasks, to strengthen a causal conclusion you take the exact opposite approach that you would in a Weaken question.

In Strengthen questions, supporting a cause and effect relationship almost always consists of performing one of the following tasks:

A. Eliminate any alternate causes for the stated effect
Because the author believes there is only one cause (the stated cause in the argument), eliminating other possible causes strengthens the conclusion.

B. Show that when the cause occurs, the effect occurs
Because the author believes that the cause always produces the effect, any scenario where the cause occurs and the effect follows lends credibility to the conclusion.This type of answer can appear in the form of an example.

C. Show that when the cause does not occur, the effect does not occur
Using the reasoning in the previous point, any scenario where the cause does not occur and the effect does not occur supports the conclusion. This type of answer also can appear in the form of an example.

D. Eliminate the possibility that the stated relationship is reversed
Because the author believes that the cause and effect relationship is correctly stated, eliminating the possibility that the relationship is backwards (the claimed effect is actually the cause of the claimed cause) strengthens the conclusion.

Conclusion : smoking → depression

(A) Participants who were depressed at the start of the study were NO MORE LIKELY to be smokers after one year than those who were not depressed.


E. Show that the data used to make the causal statement are accurate, or eliminate possible problems with the data
If the data used to make a causal statement are in error, then the validity of the causal claim is in question. Any information that eliminates error or reduces the possibility of error will support the argument.