ENGLISH:
This research focused on analyzing the implementation of the I Spy Game in improving students’ vocabulary mastery and determining whether there was a significant difference in vocabulary mastery between students who were taught using the I Spy Game and those who were not taught using the I Spy Game in the eighth grade of SMP N 1 Namang. The study utilized a quantitative approach with a quasi-experimental research design.This study was conducted at SMP N 1 Namang. The population of this study consisted of all eighth-grade students, totaling five classes. The sample consisted of 63 students from two classes: Class VIII E as the experimental group with 32 students and Class VIII B as the control group with 31 students. Both groups were given a pre-test and a post-test focusing on recount texts to measure students’ vocabulary mastery of action verbs and concrete nouns. The research data were processed using SPSS version 26. The observation results showed that the students were actively involved during the I Spy game. They also cooperated with their teammates and demonstrated enthusiasm and motivation to compete with other groups. The statistical results indicated that the experimental group’s average post-test score was 74.84, whereas the control group’s average score was 64.75. The difference in mean scores between the two groups was 10.86, with a standard error of 2.605. The two-tailed significance value was 0.000. The obtained t-value of 3.872 exceeded the critical t-table value of 2.00 at the 0.05 level of significance with 61 degrees of freedom. Thus, the null hypothesis (H₀) was rejected and the alternative hypothesis (Hₐ) was accepted. Based on the analysis results, a significant difference in vocabulary mastery was observed between students who had been taught using the I Spy Game and those who had not. In summary, the findings demonstrated that the implementation of the I Spy Game was able to support students in improving their vocabulary mastery.