This study verifies the necessity of adding 'educational institution' as a metadata variable to the National Institute of Korean Language's Korean Learner Corpus by comparing a single-institution corpus (Yonsei University Korean Language Institute) with the multi-institution integrated corpus (NIKLC). Sub-corpora were constructed from beginner-level (1-2) writing samples, controlling for variables such as proficiency, nationality, topic, genre, and token count. Analyses included lexical diversity, average sentence length, chi-square tests, and log-likelihood ratio. Results showed statistically significant differences (p<0.001) in lexical distribution and morpheme usage, manifesting as institutional variations in style (declarative vs. polite endings) and vocabulary choice ('한국어' vs. '한국말'). These findings demonstrate the independent impact of institutional factors on learner language, proposing the addition of institution variables to enhance the balance and research potential of the NIKLC corpus.