A Poor Trick
For most people, a magician's trick does not seem so magical once its secrets are revealed. If one can see the magician pull a card out of his sleeve, the trick will not have the same mysterious power as if the sleight-of-hand remains hidden. On occasion, research studies performed by poverty activist groups employ analogous statistical tricks and, far too frequently, the audience, not well-versed in the complexities of these manoeuvres, is held in awe. This article is about one such trick.
With much fanfare, the Canadian Council on Social Development recently released a study entitled "Income and Child Well-being: A New Perspective on the Poverty Debate," by David P. Ross and Paul Roberts (1999). The study presents a number of handsome graphs showing family income versus various "elements of child development." The authors note that "in 80 percent of the variables examined, the risks of negative child outcomes and the likelihood of poor living conditions were noticeably higher for children living in families with annual incomes below $30,000."
The question the authors sought to answer was, "What if producing healthy children was the main objective of anti-poverty efforts in Canada?" Their interpretation of the charts led them to conclude that poverty lines should be set at $30,000 to $40,000 per year. This level of family income, they believe, is necessary to ensure a more equal level of opportunity for Canada's children.
This study captivated the Canadian media. National Post columnist Andrew Coyne adjudged the report "remarkable" and parroted many of the study's findings and conclusions.1 A Canadian Press article ran with the headline, "Families need $30K income for kids' health."2 A trio of authors in the Winnipeg Free Press called it "a more reasoned approach to measuring poverty."3 The magicians' tricks indeed have impressed their audience.
Certainly we do not argue with the data as presented, for there is no reason to believe that it is manipulated. One may, however, debate the implicit assumption of the study: that family income, after basic needs are met, is a significant determinant of child outcomes. This assertion, while seemingly intuitive, is seriously questioned by the earlier work of University of Chicago sociologist Susan E. Mayer.
Mayer's thesis, as outlined in her Harvard University Press book What Money Can't Buy: Family Income and Children's Life Chances (1997), is as follows: assuming that certain skills, qualities, and attitudes are valued in the work place, those possessing these skills will tend to earn more money. Also, assuming that certain skills, qualities, and attitudes are required for raising children, those possessing these skills would tend to be more effective parents and have more socially and academically successful children. What would happen if a couple with the first set of skills also had the second set? If one were to graph family income against "elements of child development," indeed, it would show that those with higher family incomes would generate better results. The "cause," however, would not be parental income but, rather, the underlying set of parental characteristics.
Such an assertion stands in stark contrast to Ross and Roberts' theory. Both hypotheses explain the results of the graphs. However, while one implies an expansive role for government, the other suggests a more conservative approach. One might be tempted to accept the hypothesis that best fits one's own biases.
However, Mayer provides more than simply a plausible explanation - she also provides statistical (rather than graphical) evidence in support of her argument. Mayer finds that once parental characteristics are properly controlled for, family income has comparatively little influence on outcomes.
Her statistical analysis is also strengthened by innumerable academic references reaching a similar conclusion.
While Mayer's research results do not offer the simplistic visual appeal of Ross and Roberts' conclusions, her thesis is more intellectually satisfying. In fact, the "income is everything" magicians will require two bags full of tricks to deflate Susan Mayer's well-supported conclusions.4
Notes
- Andrew Coyne, "Drawing the Poverty Line," National Post, May 14, 1999.
- Sue Bailey, "Families Need $30K Income for Kids' Health," Edmonton Journal, May 19, 1999.
- Jim Silver, Darren Lezubski, and Errol Black, "Poverty in City High and Rising," Winnipeg Free Press, October 6, 1999.
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