The term scientific inquiry as manifest in different educational settings covers a wide range of diverse activities. The differences in types of scientific inquiry can be organized along a continuum according to the degree of teacher control and intellectual sophistication involved in each type of inquiry. Types of scientific inquiry can also be defined according to whether they produce cultural knowledge or personal knowledge. Authentic scientific inquiry is defined according to five characteristics: devel- ment of personal and cultural knowledge; contextualized scientific knowledge; the progression toward high-order problem solving; social interaction for scientific goals; and scientific inquiry as a multi-stage and multi-representational process. The definition of scientific inquiry that forms the basis for the development of an assessment program consists of a two-part analytical frame: the definition of knowledge types relevant to scientific inquiry and the definition of an organi- tional frame for these knowledge types. Four types of knowledge are significant for the definition of a specific scientific inquiry program: cognitive knowledge, physical knowledge, represen- tional knowledge, and presentational knowledge. All four of these knowledge types are considered significant. These four types of knowledge are organized in a framework that consists of two intersecting axes: the axis of knowledge types and the axis of stages of a scientific inquiry. This framework describes scientific inquiry as multi-stage process that involves the development of a series of in-lab outcomes (represen- tions) over an extended period of time.