| This study examined the effect of a lexicon enhancement program on students categorized as lower SES, determined by whether or not they qualified for the federal free or reduced lunch program. Specifically, the performance of lower SES students on measures of vocabulary learning and reading ability were compared to classmates who did not qualify for the federal program (higher SES). Forty-six 4th grade students from the Grand Forks Public School district participated in the study. Students from the lower SES and higher SES group were randomly assigned by classroom to be either in the intervention or the control group, with the intervention group receiving vocabulary instruction of either academic or tier II words through a lexicon enhancement program. Student's vocabulary knowledge was assessed using the Zero-One-Two (Robinson, 2013). Reading knowledge and vocabulary knowledge were compared using the Measures of Academic Progress (MAP), a standardized, computerized test. Results revealed that there were no significant differences between the two SES groups on the Vocabulary and Reading RIT of the MAP test. Significant differences did exist on the Zero-One-Two between the intervention and control group, { F (1,4) = 8.08, p = .01, power = .55}, Vocabulary RIT of the MAP {F (1,4) = 4.135, p = .05, power = .51}, and the Reading RIT of the MAP {F (1,4) = 8.42, p = .01, power = .81}. |
