their ability to talk and think about the concept of color. In the same way, it is difficult for a student to think about a concept if he or she doesn’t know the word for it. One final explanation for the correlation between vocabulary knowledge and intelligence may have to do with the use of vocabulary-based tasks on intelligence tests. If an intelligence test asks a student to select the appropriate use of a specific word, the student’s success with that task is directly related to his or her knowledge of that word. Whatever the reason for the correlation between vocabulary and intelligence, Stahl and Nagy’s (2006) statement holds true: “Words divide the world; the more words we have, the more complex ways we can think about the world” (p. 5).
The Effects of Vocabulary Instruction
Given the importance of vocabulary knowledge to academic success, one might assume that vocabulary instruction is of primary importance in most schools. However, Marzano (2004) reported that “uniform and systematic vocabulary instruction is scarce in U.S. schools” (p. 62), citing previous researchers (Durkin, 1979; Roser & Juel, 1982) who found that vocabulary instruction consumed less than one-half of one percent of instructional time in schools. The authors of the CCSS bemoaned the fact that “vocabulary instruction has been neither frequent nor systematic in most schools” (NGA & CCSSO, 2010a, p. 32) and cited a number of research studies (Biemiller, 2001; Durkin, 1979; Lesaux, Kieffer, Faller, & Kelley, 2010; Scott & Nagy, 1997) to support their assertion.
A number of meta-analyses have examined the effects of vocabulary instruction and intervention on students’ comprehension, oral language, and print knowledge. A meta-analysis is a statistical technique that compiles a large number of studies on a specific topic or instructional strategy (such as direct vocabulary instruction) in order to compute the average effect for that strategy. In other words, a meta-analysis seeks to quantify the overall effectiveness of a given strategy across a number of studies. This effectiveness is often reported using a number called an effect size. In educational research, effect sizes around 0.15–0.20 are considered small, 0.45–0.50 are considered medium, and 0.80–0.90 are considered large (Cohen, 1988; Lipsey, 1990). The higher the effect size, the more effective the strategy.
Effect sizes are interpreted differently from correlations (discussed previously) because effect sizes commonly represent a student’s expected improvement if they are exposed to a specific strategy. Correlations simply describe the relationship between two variables. So, as illustrated previously in table 1.2 (page 8), intelligence and vocabulary are highly correlated. That is, as one increases, so does the other. For correlations, the closer the decimal number is to 1.00, the stronger the relationship. Although effect sizes are also expressed using a decimal number, they are commonly interpreted in terms of how many standard deviations a student can be expected to improve as the result of a strategy’s use. So, an effect size of .40 might be interpreted to mean that a student’s performance would be expected to improve four-tenths of a standard deviation when a specific strategy is used.
Effect sizes are often translated into expected percentile gains. For example, Steven Stahl and Marilyn Fairbanks’s (1986) meta-analysis found that if a teacher used direct vocabulary instruction, a student at the 50th percentile would be expected to improve to the 83rd percentile. In comparison, a student who didn’t receive direct vocabulary instruction would be expected to remain at the 50th percentile. Table 1.3 shows effect sizes from various meta-analyses on direct vocabulary instruction with their corresponding percentile gains, including the Stahl and Fairbanks example.
Table 1.3: Meta-Analyses on the Effects of Direct Vocabulary Instruction
a As reported in Marulis & Neuman, 2010.
b As reported in Hattie, 2009.
Stahl (1999) pointed out that direct vocabulary instruction can have a significant impact on students whose vocabularies are small or whose vocabulary growth is slower than their peers’.
If one can teach 300 words per year, this will be a larger percentage of words for a child who might ordinarily learn 1000 words a year … than it would be for a child who would ordinarily learn 3000 or 5000 words. (p. 13)
Over the past three decades, Isabel Beck, Margaret McKeown, and their colleagues (Beck & McKeown, 1991, 2001, 2007; Beck, McKeown, & Kucan, 2002, 2008; Beck, Perfetti, & McKeown, 1982; McKeown, Beck, & Apthorp, 2010; McKeown, Beck, Omanson, & Perfetti, 1983; McKeown, Beck, Omanson, & Pople, 1985) have researched direct vocabulary instruction and concluded that the characteristics of effective direct vocabulary instruction are “frequent exposures to the words, encounters in multiple contexts, and deep or active processing of the words” (McKeown et al., 2010, p. 1). To summarize, the research on the effectiveness of direct vocabulary instruction is strong. Direct instruction about a targeted set of vocabulary terms helps students learn new words and gain the vocabulary knowledge they need for success in school.
As shown in this chapter, vocabulary development and knowledge are crucial for students’ success. Vocabulary is a fundamental aspect of reading and literacy, and it also allows students to think about information and experiences in broader and deeper ways. However, students from lower-SES families often enter school with smaller vocabularies than their higher-SES counterparts. This disadvantage can affect their literacy abilities, their interest in reading, and their development of important mental processes. The good news is that direct vocabulary instruction can increase students’ vocabularies and help them gain the vocabulary knowledge they need for success in school. Research provides support for the effectiveness of direct vocabulary instruction and guidance about the characteristics of that instruction. In the next chapter, we present a six-step process based on those characteristics that teachers can use to develop their students’ knowledge and familiarity with terms from the CCSS.
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A Six-Step Process for Vocabulary Instruction
Vocabulary knowledge develops gradually over time. Therefore, vocabulary instruction should be thought of as a process—not a singular event. The following depiction is a useful way of thinking about vocabulary development.
The first few times we encounter an unknown word, we create a container for that word in our brains. As we encounter the word more and more, we gradually fill up that container with bits of knowledge about the word: what it means, how to pronounce it, how to spell it, how it is used in sentences, what other words are normally used with it, its role in sentences, how often it is used, and how it is related to other words (Nation, 1990), among other things. Words whose containers are mostly full are generally the ones we use in our speech and writing. Words whose containers are half full or less are those we understand but don’t use. Mostly empty containers contain words we profess not to know but are still able to answer questions about or distinguish between their correct and incorrect usage. Francis Durso and Wendelyn Shore (1991) and Mary Curtis (1987) found that even when people reported that a word was unknown, they were able to identify sentences in which it was used correctly, correctly identify its synonyms, and correctly answer questions about it.
The metaphor of words as containers is useful because it highlights the fact that direct vocabulary instruction does not necessarily have to produce in-depth understanding of vocabulary terms to be useful. Marzano (2004) stated that “the goal of direct vocabulary instruction is to provide students with a surface-level, not an in-depth, understanding of vocabulary terms” (p. 120). Similarly, Nagy and Herman (1987) wrote:
Although a strong case can be made for rich, knowledge-based
