The management of a shoe manufacturing company wants to lower the cost

I got it wrong initially but of course A makes sense. The manager is saying that the program is useless because the waste per person increased

But this increase could be due to there being a lot fewer people so the program might have reduced the overall waste, but the waste per person still increased even though the program worked. So it is assumed that the number of people isn't changing, just the waste per person is.

Don't you thing if the option "A" were - "The number of employees assigned to the manufacturing department was not significantly lower three years ago that it is at present." then it would have made more sense ?

GMATNinja please help

The question is hard because I still don't understand why the option A is right. I was in favour of the option B.

Since this is a question of assumption. So when we take option D and use negation wont it actually distort the conclusion and hence would be the right option? (Conclusion being "making further changes will not bring any benefit" )

Let me try to explain my thinking process here - I chose A.

The conclusion here is that changing the quality control program will not bring any benefit since it increased the waste level per employee after certain changes were made to the program three years ago.

A. The number of employees assigned to the manufacturing department was not significantly higher three years ago than it is at present. - CORRECT - try to negate; if the number of employees was significantly higher three years ago, then of course the waste level per employee has increased since there are fewer employees to distribute the waste on. The manager assumes that the number of employees is still the same and therefore, there was no benefit in changing the quality control program
B. The quantity of wastage has not decreased in last 3 years. - this doesn't impact the argument. even it has decreased, maybe the management wants to lower it anyway
C. The company profitability has not declined in the last three years. - out of scope; profitability doesn't help us here
D. The change in quality control program may adversely affect the volume of waste per employee. - the manager actually states that changing the quality control program would not provide any benefit at all
E. The quality of shoes manufactured by the company has remained the same as it was 3 years ago. - out of scope

Hope that helps

Understanding the argument -
The management of a shoe manufacturing company wants to lower the cost of production by reducing wastage in its manufacturing process. - Premise.

Goal - Lower the cost of production
Plan - Reduce wastage in its production.

The management believes that the wastage can be reduced substantially through change in quality control program. - Opinion.

However, according to a middle level manager, since the waste level per employee has increased significantly after certain changes were made to the program three years ago, making further changes will not bring any benefit. - Contrast + supporting premise + conclusion.

Option Elimination -

Two missing premises or minimum conditions can help middle-level managers conclude to hold.
1. "certain changes" made were the best possible attempt the company could make. What if, those were some half-hearted attempts, and we compare apples vs. oranges?
2. He goes to the level of waste per employee. What if the base has been reduced while the numerators stay the same? This will also increase the waste per employee. Yes.

A. The number of employees assigned to the manufacturing department was not significantly higher three years ago than it is at present. - Say the total waste is 100 units and the number of employees three years ago was 50. Now, while the total waste has remained the same, the number of employees is 10. So total waste per employee has increased from 2 units to 5 units. But has the total waste increased? No. So, this is a solid missing premise that can help the manager's level conclusion hold.

B. The quantity of wastage has not decreased in last 3 years. - At best, a weakener.

C. The company profitability has not declined in the last three years. - Is the middle-level manager even talking about the profitability? No. Out of scope.

D. The change in quality control program may adversely affect the volume of waste per employee. - This is not the right way to strengthen. It's as if someone says 20 units of vitamin D in the blood is the maximum limit one needs to get the best bone benefit. And to strengthen, someone says, beyond 20 has adverse effects. No, maybe more than 20 has no additional benefit; it's just a waste. It doesn't necessarily need to be some negative effect. Likewise, in this case, the manager says making further changes will not bring any additional benefit. We don't need to say that making further changes is detrimental. That is a poor way of strengthening one's argument.

E. The quality of shoes manufactured by the company has remained the same as it was 3 years ago. - Out of scope.