It is helpful to think in terms of two basic kinds of change: piecemeal and systemic. Piecemeal change leaves the structure of a system unchanged. It often involves finding better ways to meet the same needs, such as using an analogy to help your students learn the science concepts you taught in an otherwise similar manner last year. In contrast, systemic change entails modifying the structure of a system, usually in response to new needs. References: Reigeluth, C. M. (1999). What is instructional-design theory and how is it changing?