Re: ADDIE, SAM, and Pebble-in-the-Pond Models

A response to Chapter 4, “SAM and Pebble-in-the-Pond: Two Alternatives to the ADDIE Model,” in Trends and Issues in Instructional Design and Technology


Compare and contrast the ADDIE, SAM, and Pebble-in-the-Pond models. Discuss strengths and weaknesses of each model. You are encouraged to utilize texts as well as graphs to share your information.


Unfortunately, some of ADDIE’s strengths are connected to its weaknesses. Because of the sequential order, an error or misjudgment at the beginning is often carried through the process. The documentation for this model is laborious and produces a written plan that is essentially an abstract concept until it the implementation phase, at which point major revisions of the project could be costly, if not impossible. The written plans of the instructional designer are subject to misinterpretation by others and the proposal is a description of what to do, but not necessarily how to do it. In all of this, it is easy to lose sight of the learner in lieu of focusing on the instruction (Branch, 2017, p. 24).

SAM (Successive Approximation Model) is one of the instructional design alternatives to the ADDIE model. It is a process model that relies on successive throwaway prototypes to communicate suggestions visually and provide opportunities for early and frequent formative testing of functionality (with live learners). As opposed to ADDIE’s document-heavy, abstract process, SAM’s use of prototypes throughout the project allows troubleshooting from the very beginning and makes for clearer communication of ideas and feedback between the designer and the stakeholders. SAM also develops preliminary plans for all of the content, from the beginning. Operating in this manner makes the SAM model very time-efficient, and therefore more cost-effective, in comparison to ADDIE (Allen & Merrill, 2017, pp. 33-35).

Above is the more basic SAM, which is a two-phased approach for simpler projects. The three-phased approach, for more complex projects, breaks the second phase into design and development phases. A key strength of the SAM approach is the Savvy Start where the design team meets (including stakeholders) to brainstorm the initial prototypes, constantly analyzing for weaknesses by asking themselves, “Why shouldn’t we do this?” From the outset, the team is committed to flexibility by generating multiple disposable iterations. Obviously SAM is a very creative process that keeps the end in mind from the beginning. The weakness of SAM is the possibility of getting stuck in the cycle of revision and having trouble finalizing the product (Allen & Merrill, 2017, pp. 33-35).

PEBBLE IN THE POND is another design alternative to ADDIE that is a problem-centered approach where the problem, something learners must solve, is the catalyst for instructional design. This model begins with the assumption that some initial evaluation and analysis has occurred and that the solution to the problem is instruction instead of some other option (Allen & Merrill, 2017, p. 35).

In this illustration, each concentric ring represents a step in the process of instructional design, where the problem initiates the process. The “pebble” represents the problem the student must be able to solve. The pebble is thrown into the “instructional pond,” causing a ripple that begins the design process.

  • The first ripple is the development of a prototype that illustrates the problem and how students can solve it (Merrill, 2013).
  • The second ripple is the creation and demonstration of a progressive series of prototypes that illustrate increasingly complex problem solving for students (Merrill, 2013).
  • Ripple number three is comprised of determination and demonstration of the specific skills required to respond to the problems as seen in the progression of prototypes (Merrill, 2002).
  • The fourth ripple is development of a structural framework for the problems in the progression using specific, task-centered instructional strategies and peer collaboration (Allen & Merrill, 2017, p. 35).
  • Ripple five is finalization of the prototype. Necessary components include design of “interface, navigation, and supplemental instructional materials” (Allen & Merrill, 2017, p. 35; Merrill, 2009).
  • The sixth ripple is the evaluation phase where data is collected to evaluate the course (formative evaluation) in order to make revisions to the prototype (Allen & Merrill, 2017, p. 35).

Unlike ADDIE, the Pebble model is very student-centered and learning-focused because it begins with the problem that the student must solve and demonstrates the skills necessary for students to succeed. Use of prototypes throughout the process avoids some other pitfalls of ADDIE such as inefficient use of time due to laborious documentation and miscommunication within the design team due to the abstract nature of a written plan. On the other hand, the Pebble model is limited since it lacks “the important steps of production, implementation, and summative evaluation” that are essential to the overall instructional design process (Allen & Merrill, 2017, p. 35).

Allen, M. W. & Merrill, M. D.  (2017). SAM and Pebble-in-the-Pond: Two alternatives to the ADDIE model. In Reiser & Dempsey (Eds.), Trends and Issues in Instructional Design and Technology (pp.31-41). New York, NY: Pearson.

Branch, R. M. (2017). Characteristics of foundational instructional design models. In Reiser & Dempsey (Eds.), Trends and Issues in Instructional Design and Technology (pp.23-30). New York, NY: Pearson.