In the mid-1920’s the Hawthorne Works of the Western Electric Company

This thing is painful. Good luck to us.


The word “that” always jumps out at me (more on the GMAT’s uses of “that” in this article), but I don’t think it’s doing anything wrong here: “that would investigate changes…” just modifies the “series of experiments.” No worries there.

There are plenty of other issues with (A), though. For starters, “their” isn’t quite as clear as I’d like it to be: “their” could refer to “changes in working conditions” or just “working conditions” or maybe even “experiments”. Pronoun ambiguity isn’t an absolute rule on the GMAT, and I don't think that “their” is WRONG here. But we can probably do better.

A clearer reason why (A) is wrong is the conditional verb “would investigate.” The series of experiments actually investigated those changes, so the conditional doesn’t make sense here.

Finally, I don’t think that the phrase “investigated changes… as to their effects on workers’ performance” is very direct. Why wouldn’t we just say that the experiments “investigated the effects of changes…” instead of doing this wordy, weird thing that suggests that the experiments investigated the changes themselves?

So we have plenty of pretty good reasons to eliminate (A).


(B) cleans up most of the issues that we had with (A). We don’t have any pronoun problems now, and the meaning is much clearer in general: now the experiments investigate “the effects” of changes – and that makes much more sense than investigating the changes themselves, as (A) suggested.

I’m also OK with the use of the “-ing” adjective, “investigating”, as a modifier for the “series of experiments.” (More on the GMAT’s various uses of “-ing” words in this article.)

You might also be wondering about the use of the conditional in (B). I had a problem with it in (A), because it’s a fact that the experiments actually investigated the effects of changes in working conditions; the conditional, as placed in (A), made no sense. But in (B)? The use of the conditional is in a different spot, and now it's fine: the experiments investigated the potential effects of changes in working conditions, so the phrase “effects that changes in working conditions would have on workers’ performance” is completely appropriate. Even if it sounds funny.

So let’s keep (B).


(C) is a hot mess, and it feels like the GMAT is just clowning us with this one. It’s so messy that it’s hard to even explain why it’s such a s#!t-show. Here’s a list of objections:

1. It’s awfully awkward to say “series of experiments for investigating.” No, the series of experiments actually investigated something, so “series of experiments that investigated” or “series of experiments investigating” are both fine, but “for investigating” wouldn’t work.

2. There’s no reason to include the words “what are” in this sentence; “investigating the effects” would be enough...

3. … Except that “effects in workers’ performance” makes no sense at all. I can’t even figure out what that phrase literally means.

4. “effects… that changes… would cause” is arguably redundant. If we’re already calling something an “effect”, then it’s hard to argue that we really need to restate the word “cause.”

I can’t believe I spent this much time thinking about (C). I’m mad at myself now. Moving on…


This is the answer choice that most of my students seem to fall in love with! (And you probably already know that you shouldn’t fall in love on GMAT verbal questions.) The problem here isn’t grammatical, though: it’s just that the meaning gets a little bit warped.

Let’s think about the intended meaning of the sentence: the experiments investigated the effects of “changes in working conditions”, right? The company changed working conditions, and then examined how those changes affected worker performance.

But (D) is saying something slightly different: the experiments “investigated changes in working conditions’ effects.” That’s wrong! We’re not interested in changes in the effects on workers’ performance -- the working conditions change, not the effects themselves.

Tricky, huh? So (D) is out.

Let’s line our last two options up side-by-side, to make it a little bit easier to see why (E) is wrong:

These two aren’t terribly different from each other. For starters, I think it’s a little bit clearer to just use the “-ing” adjective “investigating” to modify the “series of experiments” – there’s no reason to say “to investigate” in this case. I wouldn’t eliminate (E) based SOLELY on that issue, but it’s a small strike against (E).

The other problem with (E) is the phrase “what the effects changes…” At the very least, that’s awkward AF. You could also argue that the word “what” is just a waste of space: the experiments investigated “the effects”, so why stick “what” in there? It just doesn’t make any sense.

So (B) is the best we can do.