Manager: Our company's mail-order sales have recently increased

Good question, with a couple really important takeaways if you don't mind me breaking down your post.

1) "how can I say that the reason for decrease in mail order of other companies..."

Note that his isn't your job at all! Your job in Strengthen questions is to strengthen the exact conclusion being given, which here is "our change in policy probably caused the increase" - the problem is about this one company, not all the others.

2) "...is definitely because"

Also important - in Strengthen questions your job isn't to prove something ("definitely") but instead to find a reason that makes it more likely.

What (A) does here is take away the possibility that this particular company's online sales are up primarily because everyone's sales are up - that it isn't a consequence of anything the company itself did, just a consequence of the industry overall doing really well. But if (A) is true, then there's something that this particular company is doing that the others aren't, and one thing we do know that's a difference is that this company has free shipping and the others don't. This doesn't prove at all that the policy is the reason for the increase, but by taking away the "no, everyone's doing well" possibility it does make the conclusion more likely to be true.

Two things could be compared if those two thing are in common. The company's claim could be true if there is any evidence shows that the new policy has a good effect on company's mail-order sales, or shows that other companies that implement this new policy also enjoy increase in mail-order sales.

Only A conveys this comparision so A is the correct answer. Other choices are irrelevant to the argument.
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Argument says: Policy changes caused increase in sales (X caused Y).

Any answer saying Z caused Y or Y did not happen implies X did not happen can be correct.

Option A talks in similar lines to the latter logic above.

I also picked A but I must admit that C was pretty tempting. Can you please explain why the option cant be C?

For Strengthener type questions there must be addition of new information to the existing stimulus, check carefully , option (C) is a mere restatement of the following from the passage " This increase started around the time we started offering unlimited free shipping "

Hence, (C) may be discarded.
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In option A how can I say that the reason for decrease in mail order of other companies is definitely because they did not offer unlimited free shipping. It can also be because of other factors. Bad quality of products, damage during shipping etc.

Please help me understand this.

According to LSAT if you are able to eliminate alternate explanation then that statement is a strenthener.

What is wrong with B.

It says adveritsement was not responsible. It ineffect eliminatrd alternate explaunation.

Experts please suggest.

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Option E also correctly takes into consideration that since other companes are not offering free shipping on below $50, then this company is at the advantage.?

IMO: E is out of scope

there is no relation b/w sales and shipping.
Sales may have increased or decreased after charging $50 for Many Companies..we are not sure about it.

A shows the co-relation b/w sales and shipping ...much clear; Hence Correct

Thanks = KUDOS

IMO this should be a 600-700 level question. Passage and alternatives are pretty straight forward. Thanks.

According to me C is not the right option because it talks about increase in profits while I argument talks about increase in sales. We cannot correlate the increase in profits with increase in sales nor can we say that increase in sales and profits are the same. Hence, the option itself is out of context or irrelevant to strengthen the argument

The question solely discusses about increase in "mail-order sales". Any discussion about profit is out of scope imo.

Posted from my mobile device

Hi Expert
If i am not wrong this is cause and effect type question
Option B is providing alternate solution of incresing sales. So why optoion B is not correct.
Or is it that option B is assumption we are making here

Manager: Our company's mail-order sales have recently increased 25 percent. This increase started around the time we started offering unlimited free shipping, rather than just free shipping on orders over $50. Thus, our change in policy probably caused the increase.

Which one of the following, if true, most strengthens the manager's argument?

Hi
How is B irrelevant?
If we say company did advertise it policy of unlimited shipping then author assimption[change in policy cause increase in profit] is in question

The premise says X (unlijmited free shipping) is correlated with Y (sales increase) . The correlation might be a random correlation or a causation. The conclusion says X causes Y.

To prove the conclusion, we need to :
+ show that without X, Y doesn't exist
+ eliminate other potential reasons that might cause Y

The answer choice (A) proves the conclusion by showing that without X, Y doesnt exist.

E actually might weaken the conclusion. With E, the reason why sales increase is that other companies don't offer free shipping for order less than $50 but less that the company offer unlimited free shipping.

The company's change in policy occurred well after its competitors started offering unlimited free shipping.
I chose B.I thought this option rules out lack of competition and it is indeed the policy change that caused the increase in the sales.

I don't choose A because this is a causal argument and although it conveys that in absence of cause effect is absent, there can be many other reasons in the other companies.
Please explain where I am wrong.

Regards,
Arup Sarkar

The company's change in policy occurred well after its competitors started offering unlimited free shipping.
I chose B.I thought this option rules out lack of competition and it is indeed the policy change that caused the increase in the sales.

I don't choose A because this is a causal argument and although it conveys that in absence of cause effect is absent, there can be many other reasons in the other companies.
Please explain where I am wrong.

Regards,
Arup Sarkar