Research School Network: Reflections on professional learning in becoming a Research Lead (part 2)

Carver, R (1994) Percentage of unknown vocabulary words in text as a function of the relative difficulty of the text: Implications for instruction.

This is one of a number of studies that suggests readers need 98% familiarity with the vocabulary of a text in for comfortable comprehension. Carver classes as relatively hard for a reader a text that contains 2% of unknown words. My own very unscientific research a few years ago supported the idea that students with weaker inference skills identified a higher proportion of unknown words in a GCSE unseen text than those with good inference skills.

This meta-analysis looked at the data for 28 eligible studies examining the effect of direct instruction on reading comprehension at passage level. It concluded that there was a difference between custom and standardized measures with the effects for custom measures being larger than those obtained from standardized measures. The overall random-weighted mean effect size was 0.50, which suggests that direct vocabulary instruction does have a positive impact on reading comprehension. It also suggests the effect is greater for those students who have reading difficulties. However, it highlighted that there was no way of evaluating from the studies the optimum minutes spent per word.

The Vocabulary Enrichment Full Programme combines three existing programmes. The Vocabulary Enrichment Intervention Programme (VEIP) was the largest component which underwent a randomised controlled trial in 2006 in 21 London schools. This reported a significant impact on vocabulary test scores though trial was undertaken by its developer, Victoria Joffe, and it wasn’t reported in full. The second element of the Full Programme was Literacy Plus aimed at moving students from L3 to L4. The final element is Sounds-Write a phonics programme. The Full Programme is aimed at low-attaining Year 7 pupils and schools were encouraged to build their own scheme of work. The evaluation found there was no evidence that the Full Programme had an impact on the attainment in reading. However, the evaluators highlighted that there was great variability in the delivery of the programme between schools and that outcome was measured by the New Group Reading Test which might not be the best way to measure an improvement in vocabulary. Furthermore, many of the teachers participating in the trial felt it wasn’t suitable for higher ability students and the VEIP element was designed specifically for students with speech, language and communication needs. We want to increase the number of Tier Two words fully understood by our lower end students, most of whom are working at higher than L3 anyway.

This paper is a meta-analysis of studies focusing of the effects of vocabulary instruction on the learning of word meanings and on comprehension. This analysis was used to examine two questions: Does vocabulary instruction have a significant effect on children’s comprehension of text? What types of vocabulary instruction are most effective? In response to the first question, a mean effect size of .97 could be attributed to vocabulary instruction for comprehension of passages containing taught words and of .30 for global measures of comprehension. For the second question, it was suggested that the most effective vocabulary teaching methods included both definitional and contextual information in their programs, involved the students in deeper processing, and gave the students more than one or two exposures to the words. This supports the ‘robust vocabulary instruction as detailed by Beck et al in Bringing Words To Life which forms the basis of the direct vocabulary instruction we have introduced in school this September.