Decades of research have shown that technological change in schools depends on multiple interrelated factors. Structural equation models explaining the interplay of factors often suffer from high complexity and low coherence. To reduce complexity, a more robust structural equation model was built with data from a survey of 349 Swiss primary school teachers. It confirms that educational technology integration is dependent on individual teachers' readiness, which is in turn influenced by school readiness. Teacher readiness to integrate educational technology is based on perceived skills and beliefs. Facets of school readiness include educational technology resources in classrooms, perceived importance of technology integration, goal clarity, head teacher support, as well as formal and informal exchange among teachers.