As Ed Hirsch notes, vocabulary is a critical correlate of socioeconomic success (boldface mine):
There’s a well-established correlation between a college degree and economic benefit. And for guidance on what helps students finish college and earn more income, we should consider the SAT, whose power to predict graduation rates is well documented. The way to score well on the SAT—at least on the verbal SAT—is to have a large vocabulary. As the eminent psychologist John Carroll once observed, the verbal SAT is essentially a vocabulary test.
So there’s a positive correlation between a student’s vocabulary size in grade 12, the likelihood that she will graduate from college, and her future level of income. The reason is clear: vocabulary size is a convenient proxy for a whole range of educational attainments and abilities—not just skill in reading, writing, listening, and speaking but also general knowledge of science, history, and the arts. If we want to reduce economic inequality in America, a good place to start is the language-arts classroom.
Unfortunately, a curricular change that peaked in the 1960s (though it began in the 1930s and 1940s) weakened students’ vocabularies (boldface mine):
Early in the twentieth century, a well-meant but inadequate conception of education became dominant in the United States. It included optimism about children’s natural development, a belief in the unimportance of factual knowledge and book learning, and a corresponding belief in the importance of training the mind through hands-on practical experience. In the 1920s and 1930s, these ideas began spreading to teacher-training institutions. It took two or three decades for the new teachers and administrators to take over from the old and for the new ideas to revolutionize schoolbooks and classroom practices. The first students to undergo this new schooling therefore began kindergarten in the 1950s and arrived in 12th grade in the 1960s.
Their test scores showed the impact of the new ideas. From 1945 to 1967, 12th-graders’ verbal scores on the SAT and other tests had risen. But then those scores plummeted. Cornell economist John Bishop wrote in the 1980s of “the historically unprecedented nature of the test score decline that began around 1967. Prior to that year test scores had been rising steadily for 50 years.” The scores reached their nadir around 1980 and have remained low ever since.
Some scholars thought that the precipitous fall of verbal SAT scores simply reflected the admirable increase in the percentage of low-income students taking the SAT. But Bishop observed that the same downhill pattern had occurred in verbal scores on the Iowa Test of Educational Development—a test given to all Iowa high school students, who were 98 percent white and mostly middle-class in attitude. He argued that the declining effectiveness of American schools was a leading indicator for the shrinking income of the American middle class. The evidence today suggests that he was right. The decline in the educational productivity of our schools tracks our decline in income equality. For 30 years after 1945, Stiglitz observes, economic equality advanced in the United States; after about 1975, it declined.
Later, another Cornell scholar, the sociologist Donald Hayes, showed that the decline of the verbal SAT scores was indeed correlated with a dumbing-down of American schoolbooks. Following the lead of the great literacy scholar Jeanne Chall, Hayes found that publishers, under the influence of progressive educational theories, had begun to use simplified language and smaller vocabularies. Hayes demonstrated that the dilution of knowledge and vocabulary, rather than poverty, explained most of the test-score drop.
Vocabulary doesn’t just help children do well on verbal exams. Studies have solidly established the correlation between vocabulary and real-world ability. Many of these studies examine the Armed Forces Qualification Test (AFQT), which the military devised in 1950 as an entrance requirement and a job-allocating device. The exam consists of two verbal sections (on vocabulary size and paragraph comprehension) and two math sections. The military has determined that the test predicts real-world job performance most accurately when you double the verbal score and add it to the math score. Once you perform that adjustment, according to a 1999 study by Christopher Winship and Sanders Korenman, a gain of one standard deviation on the AFQT raises one’s annual income by nearly $10,000 (in 2012 dollars). Other studies show that much of the disparity in the black-white wage gap disappears when you take AFQT scores—again, weighted toward the verbal side—into account.
Hirsch also describes another key factor in developing larger vocabularies–a unified curriculum (boldface mine):
Four decades ago, France led the world in both academic achievement and equality of educational opportunity. Today, it’s absent from the PISA list of the highest-scoring, highest-equity nations. According to my colleagues in France, the decline began in the 1980s, when French elementary schools, which once followed a very specific sequential curriculum, began to diversify according to the American mode, with each elementary school developing its own plan.
The old French system didn’t just have coherent, cumulative elementary schools; it had coherent, cumulative preschools as well. These schools have not degenerated as the elementary schools have; indeed, the French preschool system is still the best in the world. Nearly every child in France attends a free public preschool—an école maternelle—and some attend for three years, starting at age two. The preschools are academically oriented from the start. Each grade has a set curriculum and definite academic goals, and the teachers, selected from a pool of highly qualified applicants, have been carefully trained….
Systematic schooling using a coherent and cumulative curriculum covers a wide range of domains as the years go by. The cognitive scientist Keith Stanovich has shown that the vocabulary of the classroom and of books is far richer than that of everyday conversation even among highly educated groups. Hence, as schooling covers more and more subjects, it imparts an ever-broader vocabulary. Under those conditions, disadvantaged students do have to keep successfully guessing more words than their advantaged peers do. But eventually, the knowledge and vocabulary gap is virtually closed.
Curriculum does matter–as Hirsch describes in the article (and you should read the whole thing)–a coherent and comprehensive curriculum that builds on previous knowledge can close socioeconomic gaps, especially when started early in life. But this is not sexy, nor is it cheap. Nor can politically connected educational testing companies profit from it. One of the reasons why I think Massachusetts does so well across all socioeconomic groups compared to other U.S. states is that the adoption of state standards in Massachusetts nearly twenty years ago–and their continual refinement–means that Massachusetts has a far more coherent curriculum at the state level. Additionally, students, especially those from disadvantaged backgrounds, who switch schools aren’t faced with a completely different curriculum, which provides a lot of stability.
There are things that matter other than lead poisoning, by the way…