Development of a Teacher Training Curriculum for Coding and STEM Education and its Effectiveness on Critical Thinking of School Students in Mahasarakham Province

Despite adequate personnel for STEM education, significant gaps remain in training for moderntechnologies, limiting the development of students’ critical thinking. This study employed a Research andDevelopment (R&D) design across three phases to address these gaps: (1) Current State and NeedsAssessment, (2) Curriculum Development and Implementation, and (3) Effectiveness Evaluation. Thefindings are as follows: Phase 1 revealed that schools possessed adequate personnel and institutionalsupport for coding and STEM programs. However, significant gaps were identified in staff trainingopportunities. Current instruction utilized Kidbright microcontroller boards and 3D printing at basiclevels, with limited integration of Internet of Things (IoT) and artificial intelligence (AI) technologies.Teachers expressed strong interest in professional development covering Arduino microcontrollers,Kidbright systems, sensors, AI applications, robotics, and laser cutting technologies. In Phase 2, atraining curriculum was developed incorporating three core components: (1) unplugged activitiesfocusing on impulsive force, (2) Scratch programming integrated with KidBright platforms, and (3) 3Ddesign using Tinkercad. The curriculum achieved the highest appropriateness and satisfaction ratings.Phase 3 demonstrated significant effectiveness: students taught by trained teachers showed significantlyhigher posttest scores compared to pretest results (p < .05), with notable improvements in deduction andrecognition of assumptions, indicating enhanced critical thinking capabilities. These findings suggestthat structured teacher-training programs integrating hands-on technology experiences can effectivelybridge the gaps in students’ critical thinking development, with implications for scaling professionaldevelopment initiatives and informing STEM implementation policy in similar educational contexts. Received: 19 December 2025 / Accepted: 05 February 2026 / Published: March 2026