Purpose:
 To examine the relationship between
A-level entrance examination scores and performance on the National Licensing
Examination Step 1 (NL1) among preclinical medical students. The study aimed
to identify key predictive factors and develop a model that could support
refinement of admission criteria for medical programs of Collaborative
Project to Increase Rural Doctors of Thailand.
Methods:
 A retrospective cross-sectional
study was conducted involving 92 medical students from the 24th and 25th
batches of Maharat Nakhon Ratchasima Medical Education Center. Data collected
included A-level subject scores, preclinical GPA, and NL1 performance.
Descriptive statistics were used to assess score distributions. Pearson
correlation and multiple regression analyses were performed to explore
associations and determine predictors of NL1 outcomes.
Results:
 The 24th batch demonstrated a wider
score range and lower mean values for both entrance and NL1 scores compared
with the 25th batch. Significant positive correlations were observed between
A-level scores, GPA, and NL1 performance (p < 0.01). English, Biology, and
Social studies A-level scores were positively associated with NL1 success,
whereas Mathematics showed a negative correlation. The predictive model
incorporating A-level subject scores and GPA explained 64.5% of the variance
in NL1 scores.
Conclusion:
 A-level subjects—particularly
English, Biology, and Social studies—serve as strong predictors of NL1
performance and may represent key academic competencies essential for
preclinical success. Mathematics showed limited relevance, indicating that
its weight in admission decisions may warrant reconsideration. Integration of
these predictive A-level scores with GPA may enhance the accuracy of student
selection and better prepare entrants for licensing examinations and future
success medical training.