Manager: Our company's mail–order sales have recently increased 25 percent. This increase started around the time we ...

Daniel on March 23 at 11:03PM

Doesn’t B block an alternate cause too?

I chose B, thinking this blocked an alternate cause, namely that advertising (rather than the policy change) could have caused the increase. If B were not true, then we don’t know for sure what caused the increase...was it the policy change or advertising the policy change? If our goal here is to choose the answer that strengthens by eliminating an alternate cause, I don’t understand how A does this any better than B. Please advise if I am missing something here. Thanks!

2 Replies

Shunhe on March 24 at 12:35PM

Hi @dannyod,

Thanks for the question! (B) doesn’t eliminate an alternate cause; indeed, it actually hurts the argument. If the company didn’t widely advertise its change in policy, then it’s more likely that people didn’t know about the change from free shipping on orders over $50 to unlimited free shipping, and so it would be less likely that the change in policy probably caused the increase. Note that the advertising discussed in answer choice (B) isn’t advertising in general for the company’s products, but advertising specifically for the change in policy.

(A), on the other hand, strengthens the manager’s argument, but not exactly through the mechanism of eliminating an alternate cause. (A) strengthens because it shows cases in which the cause is absent, and the effect is also absent, which strengthens the causal link between the change in policy and the increase in mail-order sales.

Hope this helps! Feel free to ask any other questions that you might have.

Daniel on March 24 at 11:37PM

That's helpful, thanks