V07-09

I don't really like this question, as I find that choice D better expresses the meaning to be conveyed than does the OA. Still, I'll give you my reasoning.

In the mid-1920’s the Clyde Fan Factory of the Bosch Manufacturing Company was the scene of an intensive series of experiments that would investigate changes in working conditions as to their effects on workers’ performance.

A. that would investigate changes in working conditions as to their effects on workers’ performance

This choice does not express clearly what is being investigated. It starts off OK, when it says "investigate changes in working conditions", but "investigate changes in working conditions as to their effects on workers’ performance" is basically meaningless. Are the effects being investigated? This choice does not say so. It basically mushes a bunch of words together to sound as if it says something.

Also, it is not the case that the experiments "would investigate" the changes. The experiments did investigate the changes.

B. investigating the effects that changes in working conditions would have on workers’ performance

This choice basically makes sense. It clearly expresses that the purpose of the experiments is to investigate the effects of changes in working conditions.

I don't really like this choice as much as I like D, though, as to me it makes more sense that what was being investigated was not the effect that changes "would have" on worker performance but rather the effects that changes in working conditions actually have on worker performance.

C. for investigating what are the effects in workers’ performance that changes in working conditions would cause

This version is poorly worded. What was being investigated was the effects. Saying that they were investigating "what are the effects" throws in the wording of a question, "what are", where such wording does not make sense.

Also, "effects in" is not idiomatic. The expression commonly used is "effects on", which also makes more sense than "effects in".

D. that investigated changes in working conditions’ effects on workers’ performance

To me this is the best, most concise answer. It clearly conveys that the experiments investigated the effects of the changes. I guess we could argue that it would make more sense to put "effects" directly after "investigated" as choice B does.

In any case, the difference between this choice and choice B seems to me to be a style call rather than a clear case of one choice's being better than the other.

Perhaps "investigating" in B is more continuous than "that investigated" in this choice. Tough call. Anyway, overall, after considering this question for years, I still prefer this choice.

Meanwhile, do experiments themselves "investigate". Even that idea is debatable. So, on the whole, this question is not great.

E. to investigate what the effects changes in working conditions would have on workers’ performance

In this version "to investigate" does not make as much sense as "investigating" or "that investigated". The point is not that the experiments were merely "to investigate". The experiments actually did investigate. This point is a minor one, but it contributes to the elimination of this choice.

The big issue with this choice is the addition of the word "what". This word is totally unnecessary, and its presence results in the sentence's conveying a completely muddled meaning. This version conveys that the experiments investigated what the effects would have, as if the effects themselves would have something. You can see that this is the case by eliminating a few words to get the following:

"... experiments to investigate what the effects ... would have ..."