• Integrated STEM curriculum design underpinned by standards and quality frameworks; studies examine engineering standards’ impact, cross-disciplinary knowledge demands, and frameworks like the STEM Education Quality Framework (SQF) to guide PK-12 curriculum development [4], [3], [5], [10], [19].

• Teacher conceptions, attitudes, and beliefs toward STEM integration across pre-service and in-service contexts; papers explore varied conceptions of what STEM is and how teachers perceive integration, project-based approaches, and interdisciplinarity [2], [11], [8], [20], [19].

• Professional development and teacher preparation as key drivers of STEM teaching efficacy; evidence from inquiry-based PD, STEM certificates, and partnerships shaping teacher preparedness [1], [6], [16], [15], [10].

• Teacher knowledge and STEM conceptions as foundations for practice; research surveys and case studies indicate how teacher knowledge and conceptions influence STEM teaching quality [12], [11], [18], [2].

• Inquiry-based/project-based learning and hands-on STEM activities as mechanisms in PD and classroom practice; assessments of these approaches in varied contexts [1], [16], [8], [13], [14], [20].