GMAT : Analysis of An Argument

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An Argument

22. The following appeared in the editorial section of a newspaper.

As public concern over drug abuse has increased, authorities have become more vigilant in their efforts to prevent illegal drugs from entering the country. Many drug traffickers have consequently switched from marijuana which is bulky or heroin which has a market too small to justify the risk of severe punishment to cocaine. Thus enforcement efforts have ironically resulted in an observed increase in an illegal use of cocaine.


Discuss how well reasoned you find this argument. In your discussion be sure to analyze the line of reasoning and the use of evidence in the argument. For example, you may need to consider what questionable assumptions underline the thinking and what alternative explanations or counterexamples might weaken the conclusion. You can also discuss what sort of evidence would strengthen or refute the argument, what changes in the argument would make it more logically sound and what, if anything, would help you better evaluate in conclusion.


The conclusion in this argument is that increased vigilance by drug enforcement authorities has resulted in an increase in the illegal use of cocaine. The author reaches this conclusion on the grounds that drug traffickers have responded to increased enforcement efforts by switching from bulkier and riskier drugs to cocaine.

Presumably, the author's reasoning is that the increased enforcement efforts inadvertently brought about an increase in the supply of cocaine which, in turn, brought about the observed increase in the illegal use of cocaine.

This line of reasoning is problematic in two important respects.

In the first place, the author has engaged in Since B happened after A, B was caused by A reasoning. The only reason offered for believing that the increased vigilance caused the increase in cocaine use is the fact that the former preceded the latter. No additional evidence linking the two events is offered in the argument, thus leaving open the possibility that the two events are not causally related but were merely coincidental. This in turn leaves open the possibility that factors other than the one cited are responsible for the increase in cocaine use.

In the second place, the author assumes that an increase in the supply of cocaine is sufficient to bring about an increase in its use. While this is a tempting assumption, it is a problematic one. The presumption required to substantiate this view is that drug users are not particular about which drugs they use, so that if marijuana and heroin are not available, they will switch to whatever drug is available - cocaine in this case. The assumption does not seem reasonable on its face.

Marijuana, heroin and cocaine are not alike in their effects on users. Nor are they alike in the manner in which they are ingested or in their addictive properties. The view that drug users' choice of drugs is simply a function of supply overlooks these important differences.

In conclusion, the author has failed to establish a causal link between increased enforcement efforts and the observed increase in illegal cocaine use. While the enforcement activities may have been a contributing factor, to show a clear causal connection the author must examine and rule out various other factors.

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