The primary aims of this study were two-fold: (1) to describe average change in the written narrative performance of second grade students from the fall and spring of the school year; and (2) examine patterns of individual growth to test for Matthew effects. Participants included 299 children in second grade. Microstructural measures were derived from students' written narratives including: number of different words (NDW), total number of words (TNW), and accuracy of spelling and grammar. Significant increases in NDW, TNW, and spelling accuracy were evidenced from fall to spring. Students averaged 55 total words in the fall and averaged 69 words in the spring, with a statistically significant increase of 14 words t(299)=8.4, p<0.0001). The variance in TNW from fall to spring increased from Var=791 to Var=1005, which was a significant increase and the correlation of initial Fall TNW and growth in TNW was also significant (r = 0.39). Additionally, results from a two-level hierarchical linear model with students nested within teachers indicated that initial level of TNW predicted the change in TNW from fall to spring, with higher levels of initial TNW being related to larger gains in TNW. Significant predictors of Matthew effects included teacher or classroom and free/reduced lunch eligibility. Written personal narrative measures are sensitive to developmental change across a school year. Evidence of Matthew effects in lexical productivity suggests additional support may be warranted to ameliorate gaps in writing achievement. [This paper was published in "Reading and Writing" v33 p1377-1398 2020 (EJ1254289).]