If someone told you that the test scores people get in their late teens were highly correlated with their incomes later in life, you probably wouldn\u2019t be surprised. If I said the correlation was .35, on a scale of 0 to 1, that would seem like a strong relationship. And it is. That\u2019s what I got using the\u00a0National Longitudinal Survey\u00a0of Youth<\/a>. I compared the\u00a0Armed Forces Qualifying Test scores, taken in 1999, when the respondents were ages 15-19 with their household income in 2011, when they were 27-31.<\/p>\n Here is the linear fit between between these two measures, with the 95% confidence interval shaded, showing just how confident we can be in this incredibly strong relationship:<\/p>\n That\u2019s definitely enough for a screaming headline, \u201cHow your kids\u2019 test scores tell you whether they will be rich or poor.\u201d And it is a very\u00a0strong relationship\u00a0\u2013\u00a0that correlation of .35 means AFQT explains 12% of the variation in household income.<\/p>\n But take heart, ye parents in the age of uncertainty: 12% of the variation leaves a lot left over. This variable\u00a0can\u2019t\u00a0account for how creative your children\u00a0are, how sociable, how attractive, how driven, how entitled, how connected, or how White they may be. To get a sense of all the other things that matter, here is the same data, with the same regression line, but now with all 5,248\u00a0individual points plotted as well (which means we have to rescale the\u00a0y<\/em>-axis):<\/p>\n Each dot is a person\u2019s life \u2014 or two aspects of it, anyway \u2014 with the virtually infinite sources of variability that make up the wonder of social existence.\u00a0All of a sudden that strong relationship doesn\u2019t feel like something you can bank on with any given individual. Yes, there are very few people from the bottom of the test-score distribution who are now in the richest households (those clipped by the survey\u2019s topcode and pegged at 3 on my scale), and hardly anyone from the top of the test-score distribution who is now completely broke.<\/p>\n But I would guess that for most kids a better predictor of future income would be\u00a0spending an hour interviewing their\u00a0parents and high school teachers, or spending a day getting to know them as a teenager. But that\u2019s just a guess (and that\u2019s\u00a0an inefficient way to capture large-scale patterns).<\/p>\n I\u2019m not here to argue about how much\u00a0various measures matter for future income, or whether there is such a thing as general intelligence, or how heritable it is (my opinion is that a test such as this, at this age, measures what people have learned much more than a\u00a0disposition toward learning inherent at birth). I just want to give a visual example of how even a very strong relationship in social science usually represents a very messy reality.<\/p>\n Cross-posted at Family Inequality<\/a>\u00a0and Pacific Standard<\/a>.<\/em><\/p>\nPhilip N. Cohen is a professor of sociology at the University of Maryland, College Park, and writes the blog Family Inequality<\/a>. You can follow him on Twitter<\/a> or Facebook<\/a>.<\/span>","protected":false},"excerpt":{"rendered":" The short answer is, pretty well. But that\u2019s not really the point. In a\u00a0previous post\u00a0I complained about various ways of collapsing data before plotting it. Although this is useful at times, and\u00a0inevitable to varying degrees, the main danger is the risk of inflating how strong an effect seems. So that\u2019s the point about teen test […]<\/p>\n","protected":false},"author":287,"featured_media":62507,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[223,29,34,778,2104,274],"class_list":["post-62505","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-childrenyouth","tag-class","tag-education","tag-intersectionality","tag-knowledgeintelligence","tag-methodsuse-of-data"],"jetpack_featured_media_url":"https:\/\/thesocietypages.org\/socimages\/files\/2014\/04\/1-2-Copy11.png","_links":{"self":[{"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/posts\/62505","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/users\/287"}],"replies":[{"embeddable":true,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/comments?post=62505"}],"version-history":[{"count":5,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/posts\/62505\/revisions"}],"predecessor-version":[{"id":63168,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/posts\/62505\/revisions\/63168"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/media\/62507"}],"wp:attachment":[{"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/media?parent=62505"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/categories?post=62505"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thesocietypages.org\/socimages\/wp-json\/wp\/v2\/tags?post=62505"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"1](\"https:\/\/thesocietypages.org\/socimages\/files\/2014\/04\/1-2-Copy6-500x319.jpg\")
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