Correctly measuring the productivity of service workers is complex. Consider, for example, postal workers: they are often said to be more productive if more letters are delivered per postal worker. But is this really true? What if more letters are lost or delayed per worker at the same time that more are delivered?

The objection implied above to the productivity measure decribed is based on doubts about the truth of which of the following statements?

(A) Postal workers are representative of service workers in general.
(B) The delivery of letters is the primary activity of the postal service.
(C) Productivity should be ascribed to categories of workers, not to individuals.
(D) The quality of services rendered can appropriately be ignored in computing productivity.
(E) The number of letters delivered is relevant to measuring the productivity of postal workers.

The correct answer choice is (A). Is the author asking for the assumptions made in the argument? If yes, how does (D) account for the underlying assumption? Please help to understand.

Thanks
GMAT 2007

Please let people know if this is OG11, OG10 or the Verbal supplement. Also, you first mention that the correct answer is A but then ask how D works. I think the answer is D, so I'm just going to assume your reference to A was a typo. Please clarify.

Measuring productivity is complex. Example: postal workers. Some assume that they are more productive if they deliver more letters per worker. But if the error rate also increases, does that really constitute being "more productive"?

The author begins by implying that it is common thinking to measure productivity just by # of letters delivered per person. If, however, the overall quality of service suffers (60% of all letters will be delivered by one person! But the rest will be permanently lost.) then, this author thinks, we can't really consider that to be more productive. Essentially, the author is saying that we have to factor in not just one basic factor but others (service levels in this example) when measuring productivity.

The question says that the author's objection is "based on doubts about the truth of" one of the answers. So it's asking us why some people think that postal workers are more productive simply if the # of letters per carrier figure increases - and the author does not agree with that statement. The author thinks service levels should be factored in; the "others" don't consider service when measuring productivity.

Ans is D in OG.
This is OG 10.

Thanks Stacey for that explanation

Thanks for clarifying!