Merrill's Instructional Transaction Theory (ITT)

Instructional transactions are "all of the learning interactions necessary for s student to acquire a particular kind of knowledge or skills" (Merril, 1999). Instructional Transaction Theory (ITT) is an attempt to identify the patterns of the transactions and thus, to develop instructional algorithms to promote an appropriate instructional transactions. The instructional algorithms operate on a set of 'knowledge objects' incorporating three major types of instructional strategies: presentations, practices and learner guidance. In other worlds, ITT intends to identify what are the knowledge components required for a given type of instruction, and develop instructional strategies of presentation, practice and learner guidance to represent these knowledge components to facilitate instructional design (Merrill, 1999.)

Merrill's conception of 'knowledge object'
Instructional strategies in ITT have described as algorithms for manipulating the elements for knowledge objectives. But what are knowledge objects? According to Merril (1999), knowledge objects are containers consisting of compartments (slots) for different related elements of knowledge. The content of knowledge objects consists of:

Jones, Li, and Merrill (1990) identified four types of knowledge objects:

  1. Entities: objects in the world, such as device, persons, creatures, places and symbols
  2. Properties: quantitative or qualitative attributes of entities
  3. Activities: actions that the learner can take to act on objects in the world
  4. Processes: events that occur in the world that change the values of properties of an entity

ITT provides more precise ways to describe knowledge representation, instructional strategies, and instructional-design prescriptions, and makes automated instructional design a possibility. The goals of ITT can be summarized as development of:

According to ITT, the learning environment is built on the following elements:

  1. The instructional goal that it is designed to promote
  2. The knowledge structure required by the knowledge environment: The structure is determined by the relationship among processes, entities, and activities from the knowledge objects.
  3. The general simulation engine which operates on the knowledge structure to present activities and processes that occur in the world
  4. The learning activities of exploration by which the student interacts with the learning environment: the learning activities are carried out under the instructional strategies of presentation, practice and learning control. An instructional strategy incorporates all of the conditions for teaching a given type of learning an instructional transaction.

Merrill, Jones and Li (1992) previously identified 13 classes of instructional transactions (Merrill, Jones, & Li, 1992) in three categories: component, abstraction and association. These instructional transactions include: IDENTIFY (component or naming or parts-of …, also related to "facts" in CDT ), EXECUTE (activity or procedures or how-to …, "procedures" in CDT), and INTERPRET (process or what-happens …, "principles" in CDT).

Contributions of ITT
Reigeluth (1999) complemented ITT in its efficiency of time saving in design and development of instruction and its sound theoretical foundations.


Merrill, M. D. (1999). Instructional design based on knowledge objects. In C. M. Reigeluth (Ed.), Instructional design theories and models: A new paradigm of instructional theory, Volume II, pp. 397-424. Mahwah, NJ: Lawrence Erlbaum Associates.

Merrill. M. D., Li, Z., & Jones, M. K. (1991). Instructional Transaction Theory. Educational Technology, 31 (6), 7-12.

Merrill, M. D., Jones, M. K., & Li, Z. (1992). Instructional Transaction Theory: Classes of Transactions. Educational Technology, 32(6), 12-26.

Reigeluth, C. M. (1999). (Ed.), Instructional-design theories and models: An new paradigm of instructional theory, Volume II.. Mahwah, NJ: Lawrence Erlbaum Associates.