Question

A factory was trying out a new process for producing one of its products, with the goal of reducing production costs. A trial production run using the new process showed a fifteen percent reduction in costs compared with past performance using the standard process. The production managers therefore concluded that the new process did produce a cost savings. Which of the following, if true, casts most doubt on the production managers' conclusion?

• A. In the cost reduction project that eventually led to the trial of the new process, production managers had initially been seeking cost reductions of fifty percent.
• B. Analysis of the trial of the new process showed that the cost reduction during the trial was entirely attributable to a reduction in the number of finished products rejected by quality control.
• C. While the trial was being conducted, production costs at the factory for a similar product, produced without benefit of the new process, also showed a fifteen percent reduction.
• D. Although some of the factory's managers have been arguing that the product is outdated and ought to be redesigned, the use of the new production process does not involve any changes in the finished product.
• E. Since the new process differs from the standard process only in the way in which the stages of production are organized and ordered, the cost of the materials used in the product is the same in both processes.

Hint:

When an argument concludes that X caused Y, a powerful way to weaken it is to show that Y also occurred when X was not present. This introduces an alternative cause and breaks the assumed causal link. This is often called a "control group" argument.

Answer 1

The Correct Option is C

Step 1: Understanding the Argument:
- Premise: A trial of a new process showed a 15% reduction in production costs.
- Conclusion: The new process causes cost savings.
- Task: Cast doubt on the conclusion. We need to find information that suggests the 15% cost reduction was caused by something *other than* the new process.
Step 2: Analyzing the Argument's Logic and Finding the Gap:
The argument assumes a causal link: because the cost reduction happened *during* the trial of the new process, the new process *caused* the cost reduction. This is a classic correlation-is-not-causation scenario. To weaken it, we need to introduce a plausible alternative cause for the observed effect (the cost reduction).
Step 3: Evaluating the Options:
(A) ...managers had initially been seeking cost reductions of fifty percent. The original goal is irrelevant to whether a 15% saving was actually achieved by the process. This doesn't weaken the conclusion.
(B) ...cost reduction...was entirely attributable to a reduction in the number of finished products rejected by quality control. A reduction in rejected products is a form of cost saving directly related to a production process improvement. This would actually *strengthen* the conclusion by explaining *how* the new process saved money.
(C) While the trial was being conducted, production costs at the factory for a similar product, produced without benefit of the new process, also showed a fifteen percent reduction. This is a very strong weakener. It introduces a control group (the similar product) that also experienced the same cost reduction without the new process. This suggests that some other factor, common to the whole factory (like cheaper raw materials, a new factory-wide efficiency program, or lower energy costs), was the real cause of the cost reduction, not the new process itself.
(D) ...the use of the new production process does not involve any changes in the finished product. This is irrelevant. The conclusion is about the cost of the *process*, not the design of the product.
(E) ...the cost of the materials used in the product is the same in both processes. This eliminates one possible source of cost savings (materials) but doesn't weaken the overall conclusion, as the savings could have come from labor, efficiency, energy, etc. It limits the explanation but doesn't undermine the conclusion.
Step 4: Final Answer:
Option (C) provides the most compelling evidence to doubt the conclusion by suggesting that an external factor, and not the new process, was responsible for the cost savings.