Reigeluth (1999) groups instructional conditions, outcomes, and values about instruction into the category of "situationalities" - knowing when certain methods are likely to achieve desired instructional outcomes based on specific instructional conditions. When developing instructional theory, it is important to be able to describe instructional methods and the specific situationalities in which they should be used.

Several prominent educational psychologists have also argued for the consideration of "situationalities" when designing instruction or trying to understand the learning process, though they do not necessarily use the term "situationality." Snow argued consistently over many years of research that understanding student aptitude and creating effective instructional environments requires an acknowledgement of not only student differences, but also differences in the instructional tasks and processes, knowledge domain, instructional treatment program, specific learning situation, and learner population group (Snow, 1986; Snow, Corno, & Jackson, 1996; Snow & Lohman, 1984; Snow & Swanson, 1992). Sternberg has stressed the importance of acknowledging differences among student learning, or thinking, styles, and modifying instruction (teaching methods) to more appropriately match student thinking styles (Sternberg, 1994a). Sternberg has mapped student thinking style types onto various types of teaching methods and assessment styles, arguing that matching assessment type with student thinking style leads to more successful learning outcomes, as measured by assessment (Sternberg, 1994b). Using Sternberg's approach, student thinking style would be an important instructional condition to consider when selecting instructional methods.

Reigeluth (1999) further explains the characteristics of instructional theory as being probabilistic as opposed to deterministic. In other words, instructional theory should provide guidance that is likely to lead to the desired learner and instructional outcomes, but there is no 100% assurance that outcomes will be achieved. There are too many situations and variables interacting in any instructional context to completely address with any one instructional theory. This leads to the importance of instructional values in deciding which learning and instructional goals to pursue, which methods (among options) are chosen to attain those goals, and which criteria are chosen to assess which method works best in any given learning context.

Therefore, instructional design theories focus on design (what should be done) and offer methods that are likely to work under the specified conditions to attain given outcomes. Foundational values about learning determine the learning goals and influence the methods that will be selected based on the situationalities of any given learning environment.

To review briefly, the term "situationalities" is used to describe features of a particular instructional design theory or instructional environment that influence the selection and implementation of particular instructional strategies or methods (Reigeluth, 1999). When developing instructional theory or designing a learning environment, it is important to recognize and work within the constraints of the known situationalities in order to achieve desired instructional outcomes such as effectiveness, efficiency, aesthetic appeal, and ultimately student learning. The most appropriate element to begin with is values, since an educator's values are often the most important influence on the type of learning environment (and accompanying instructional strategies) s/he creates.