<![CDATA[Animated video may support descriptive writing by making observable features available for noticing and lexicalization; however, evidence from a one-group design must be interpreted as within-group change rather than as a causal effect. This study investigated changes in tenth-grade students’ descriptive-writing performance after animated-video-supported instruction at SMAN 1 Lhoknga, Aceh Besar. A one-group pretest–posttest design involved 25 students from class X-3, selected purposively from a Grade X population of 240 students in the 2023/2024 academic year. Students completed an initial descriptive paragraph, four instructional sessions combining animated video, printed still images, vocabulary prompting, guided planning, and paragraph writing, and a comparable posttest task. Compositions were scored for content, organization, vocabulary, grammar, and mechanics. Because the paired difference scores departed from normality, the analysis used descriptive statistics, individual normalized gain, and an exact two-sided Wilcoxon signed-rank test. The mean increased from 46.44 (SD = 8.94) to 77.72 (SD = 4.95), a gain of 31.28 points; all 25 students obtained higher posttest scores. Mean normalized gain was 57.08% (SD = 11.53), with values from 26.67% to 76.79%. The paired comparison was significant, W = 0, exact p < .001, and the rank-biserial correlation was 1.00, indicating that every observed difference favored the posttest. The findings provide strong evidence of substantial improvement within this class, but the lack of a comparison group, purposive sampling, short duration, and undocumented scoring reliability preclude attributing the gain to animated video alone. Animated video is therefore best understood as one component of a scaffolded writing sequence that also requires explicit language instruction, practice, and feedback.]]>
