Level of Abstraction Describes the concreteness / abstractness of a concept: (a) Very abstract concepts are theoretical, may not be directly measurable, defined by concrete concepts, inclusive of concrete concepts, disassociated from any specific instance, independent of time and space, have more general descriptors, may not be clinically useful for planning treatment. (b) Concrete concepts are observable and measurable, limited by time and space, constitute a specific category, more exclusive, name a real thing or class of things, restricted by nature, may be clinically useful for planning treatment.