The education sector in Kenya faces challenges related to secondary school systems, particularly in terms of adoption rates for new methodologies and technologies. The study employs a comprehensive search strategy across relevant databases, including Scopus and Web of Science. A quality assessment framework is applied to evaluate studies based on their methodology, results, and implications. A significant proportion (70%) of reviewed studies utilised multilevel regression analysis for measuring adoption rates, indicating its growing acceptance in the field. Multilevel regression analysis emerges as a robust methodological tool for evaluating secondary school systems' adoption rates, with substantial evidence supporting its use across various contexts. Educational policymakers and researchers should consider multilevel regression analysis when analysing adoption trends to enhance the accuracy and reliability of their findings. secondary schools, education systems, multilevel regression, adoption rates, Kenya The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.