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Kolodner, Janet L. and David Leake (1996). A Tutorial Introduction to Case-Based Reasoning . In Case-Based Reasoning: Experiences, Lessons and Future Directions, Leake, David (ed.). MIT Press. pp 31-65.

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Author of the summary: Jake Auxier, 1999, jauxier1@cc.gatech.edu

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Case-based reasoning advantages

Case-based reasoning cycle:

  1. Retrieve
  2. Propose ballpark solution
  3. Adaptation in problem solving CBR, Justification in Interpretive CBR
  4. Criticism of the solution; may trigger further adaptation
  5. Evaluation of the solution; may trigger further adaptation
  6. Store the solution

General knowledge, when available, can guide the choice of indices, the determination of how well a new situation matches a stored case, and the choice of adaptation strategies.

Two major functional parts of a case: (1) the lesson(s) it teaches, (2) the context in which it can teach it lesson(s), described by its indexes; designating the circumstances in which it would be appropriately retrieved.

The Content of Cases and Indexing

 The content of a case is made up of: (1) the problem/situation description, (2) the solution, and (3) the outcome. The outcome is not needed but could be added to suggest solutions that work and use cases with failed solutions to warn of potential failures.

Indexes predict a case's usefulness. Indexes should be made that describe the tasks a case can be useful for. Indexes should be abstract enough to retrieve a relevant case in a variety of future situations, and indexes should be concrete enough to be easily recognizable in future situations.

Indexing Vocabularies

Indexing vocabularies have two parts: (1) a set of descriptive dimensions and (2) a set of values along each dimension.

Defining an Indexing Vocabulary

Retrieval and Memory Update

Retrieval is done through matching and ranking procedures. Matching can use the indexes to find similar cases, but it needs to be able to distinguish which indexed features to focus on at any time.

Input to retrieval algorithms includes both a description of the new situation and also an indication of what the reasoner will use the case for.

Retrieval also depends on the retrieval algorithms used and situation assessment. Situation assessment is the process of analyzing a situation and elaborating it such that its description is in the same vocabulary as cases already in the case library.

Memory update is somewhat analogous to retrieval. Updating will look for a place to insert the new case rather than for a place to retrieve a similar case from.


Adaptation is when one takes a problem description and a solution that isn't quite right and manipulates the solution to make it better fit the problem description.

There are four general methods for adaptation:

  1. Substitution: substitute values appropriate for the new situation for values in the old solution
  2. Transformation: transform an old solution into one that will work in a new situation
  3. Special-purpose adaptation and repair: used to carry out domain-specific and structure-modifying adaptations not covered by the above methods
  4. Derivational replay: reuses the method for deriving an old solution or solution piece to derive a solution in anew situation.


This is used in interpretive CBR. Justification can be done by comparing new situations and prior cases, and by looking at what differentiates the new situation from old similar ones to ascertain whether or not the old interpretation is likely to hold.

Learning in Case-based Reasoning

A case-based reasoner's performance becomes more efficient by remembering old solutions and adapting them rather than having to derive answers from scratch each time.

Case-based reasoners become more competent over time, deriving better answers than thy could with less experience.

Where Learning Occurs

Uses of CBR

Problem Solving CBR

Interpretive CBR

Case-based Decision Aiding and Teaching

Types of Case-based System

Autonomous systems: solve problems by themselves; CHEF, JULIA, PLEXIUS, CASEY, PROTOS, HYPO.

Human-machine systems: work along with people to solve problems or interpret situations; CSI Battle Planner, ARCHIE-2, Clavier, SCIED.

Embedded systems: those in which a retrieval-only or autonomous case-based system is embedded as a component in a system with a larger purpose than problem solving or situation interpretation

Case Collection

Summary author's notes:

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Last modified: 5/9/99 12:36:41 PM