It might depend on what form of technology is being introduced. The following recent study of Interactive Whiteboard Technologies might give you an idea of the things you might want to measure:
Schipper, J. M., & Yocum, R. G. (2016). Interactive Whiteboard Technologies in High School: A comparison of their impact on the levels of measure that determine a return on investment. Journal of Educational Technology Systems, 44(4), 377-403.
-roles that the technology might play in pedagogy( tool, tutor, resource,learning environment)
-relationship of technology to educational aims and outcomes (different technologies for different types of knowledge)
-structure of existing pedagogical practices and potential changes needed
- perceptions of teachers and their understanding of how technology fits with their subject and educational philosophies
-relationship of technology to assessment practices.
All this is saying is that technologies are not a kind of a "treatment" that can simply enhance existing practices and outcomes, in my experience. Digital technologies change what happens and what counts as knowledge.
I forgot to add perhaps the most important factor:
-relationship of task to pupil's digital repertoires (technical fulency with an application and the capacity to adpt technical know how to new situations)
The technology that we choose should be engaging, motivational, culturally appropriate, easy to use, easily accessible, and also it should enhance instruction.