- Sales of Fantasy books has gone from 1 to 10 percent of total Adult Fiction sales
+
# of favorable reviews of Fantasy books has increased
→
Increased sales of Fantasy books has increased because of more favorable reviews
So this a fairly straightforward problem about correlation/causation. We have fantasy books increasing in terms of market share while number of favorable reviews are increasing "at the same time." The author concludes, "clearly the favorable reviews spawned the increased sales." How do we go about weakening this claim? Well we could show that it was something else that caused the increased sales. Maybe it was showcased on a popular morning TV show? We could also show that B→A, that increased sales led to favorable reviews (this happens, too!). We could also show the same cause in an analogous situation with a different effect. For example, we could say that certain nonfiction books have favorable reviews but did not lead to any increase in sales.
- (A) We don't care why a book gets published. We care about breaking the connection between good reviews and book sales.
(B) This is a great weakener! It shows that the book reviews don't even matter! Nobody who matters reads them! In addition, it very obviously breaks the connection between book sales and reviews by directly saying "even fewer select books to purchase on the basis of reviews." This is a very strong weakener.
(C) We don't care if they are or aren't aware. We want to break the connection between good reviews and book sales!
(D) Yea okay but why is the increase going to increase further? That is what we are really concerned about. We want to say why it is NOT the book reviews that led to these increases.
(E) Does this impact sales? Does this weaken the connection between sales and book reviews? It doesn't seem to be so.