A threshold problem with the argument involves the statistical reliability of the survey. The
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director provides no evidence that the number of respondents is statistically significant or that
the respondents were representative of auto workers in general. Lacking information about the
randomness and size of the survey’s sample, the director cannc;to make a convincing
argument based on that survey.
Even if the survey’s respondents are representative of the entire population of auto workers,
the argument relies on the assumption that the responses themselves are reliable. Yet the
director ignores the possibility that a young, inexperienced worker is less likely to be forthright
about the value of supervision--for fear of retaliation by that supervisor. For that matter,
younger workers might not have enough experience working without supervision to determine
when they are most productive. Lacking evidence that the respondents’ reports were both
truthful and meaningful, the director cannot confidently draw and conclusions about worker
productivity from them.
Even assuming that the survey data accurately reflect the auto industry, the argument
unfairly assumes that supervision affects worker productivity similarly at PPC. Perhaps PPC
employs certain unique equipment or processes that require close worker supervision--even
for older, more experienced workers. For that matter, perhaps youth or inexperience is an
advantage in working productively at PPC, whereas in the auto industry either is a
disadvantage. In short, without accounting for possible differences between PPC and auto
manufacturers the director cannot convince me that his recommendation for PPC is sound.
The argument also assumes that older people are more experienced, and thus less likely to
benefit from supervision, than younger people. Although this assumption might gen erally be
sound, it nevertheless might not hold true for workers at PPC specifically. In other words,
despite their age many younger PPC worker might be more experienced at their jobs, and
therefore more productive without supervision, than many older PPC workers.Finally, even if hiring older workers will reduce the need for supervision, the director
concludes too hastily that PPC will save money as a result. It is possible that older workers
command a higher wage than younger workers do. If so, these higher wages might offset
production gains and payroll savings accruing from reduced supervision.
In sum, the survey’s statistical reliability and its relevance to PPC is questionable. To
strengthen the recommendation the director must provide clear evidence that in the printing
industry, and especially at PPC, older workers are more experienced or otherwise can work
more productively without supervision than younger workers. To better assess the argument, I
would need a detailed cost-benefit analysis that accounts not only for gains in productivity but
also for the possible impact of hiring only older workers on total payroll costs.
Argument 75
The following appeared as part of an article in a health magazine.
"A new discovery warrants a drastic change in the diets of people living in the United States.
Two scientists have recently suggested that omega -3 fatty acids (found in some fish and fish
oils) play a key role in mental health. Our ancestors, who ate less saturated fat and more
polyunsaturated fat, including omega -3 fatty acids, were much less likely to suffer from
depression than we are today. Moreover, modern societies---such as those in Japan and
Taiwan---that consume large quantities of fish report depression rates lower than that in the
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United States. Given this link between omega -3 fatty acids and depression, it is important for
all people in the United States to increase their consumption of fish in order to prevent
depression."
The author of this article asserts that people who live in the U.S. should increase their fish
consumption in order to prevent depression. To support this assertion, the author cites the fact
that our ancestors, who were less likely to experience depression than we are today,
consumed more omega-3 fatty acids, which help prevent depression and are found in some
fish and fish oils. The author also cites the fact that in modern societies where people eat more
fish than we do the reported incidence of depression is comparatively iow. However, the
author’s reasoning is problematic in several critical respects.The first problem with the argument involves the comparatively low incidence of depression
among our ancestors. The author assumes that no factor other than the ingestion of omega-3
is responsible for this lower incidence. However, it is entirely possible that environmental or
other dietary factors are instead responsible for the lower incidence. For example, perhaps
other substances common in the U.S. diet today, and which promote depression, were not part
of our ancestors’ diets.
Another problem with the argument involves the low incidence of depression reported
among today’s fish-eating societies. To reasonably infer a causal relationship between
fish-eating and low rates of depression in these societies, two assumptions are required. The
first is that the types of fish consumed in these societies in fact contain omega-3; however the
artide provides no evidence that this is the case. The second assumption is that the reported
incidence of depression accurately reflects the actual incidence. However, it is entirely
possible that in those societies people generally do not report depression.
A third problem with the argument is that it assumes that omega-3 is only available in fish.
However, the author provides no evidence to substantiate this crucial assumption. Perhaps
people can ingest omega-3 by taking fish oil capsules rather than eating fish. Or perhaps
omega-3 is also found in other foods as well. In either case, the author cannot reasonably
conclude that we must eat more fish to ingest omega-3 and thereby help prevent depression.
Finally, in concluding that people in the U.S. must ingest more omega-3 to prevent
depression, the author infers that this is the only means of prevenl~ag depression. This
reasoning is fallacious. There might be a myriad of alternative ways to prevent depression;
moreover, experience and common sense informs me that this is indeed the case.
In conclusion, the argument is unconvincing as it stands. To strengthen it, the author must
provide clear evidence that no other factors explain the comparatively low incidence of
depression among our ancestors. The author must also show that in modem fish-eating
societies people in fact ingest more omega-3 than people in the U.S. do, and that the
incidence of depression is in fact lower in those societies. To better evaluate the argument, we
would need more information about alternative methods of preventing depression and
alternative sources of omega-3.