At LanguageHumanities, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What Is Case-Based Reasoning?

Daniel Liden
Daniel Liden

Case-based reasoning is a problem-solving method in which one develops a solution to a new problem based on past experiences with a different problem. In some cases, one may be able to completely reuse a particular solution, while in other cases the old problem provides only limited insight into the new solution. Case-based reasoning is strongly based in analogy, as individuals look to the past to find situations and problems analogous to the ones that they face in the present. It is highly relevant to the study of human decision making and to computer reasoning technology. Many researchers in the area of human decision making and problem solving believe that nearly all reasoned decisions are made from case-based reasoning.

One can apply case-based reasoning in a variety of different ways based on one's needs in a given situation. A solution to an older problem can be reused to solve a new and analogous problem or can at least suggest a method for solving the new problem. One can use such reasoning to modify a solution to the new problem that doesn't quite work right or to predict potential issues with a new solution. After coming up with a solution to the new problem, one can use analogous past situations to analyze the new solution in order to determine why it worked and to look for potential shortcomings.

Judges often base their decisions on previous similar legal cases.
Judges often base their decisions on previous similar legal cases.

Four primary steps characterize case-based reasoning. When a new problem is identified, one must first recall similar past problems. Upon recalling past problems, one reuses a solution or adapts it to the new situation. After this, one must test the new solution to see if it works for the new problem just as it worked for the analogous older problem and must revise the new solution accordingly. Lastly, after finding a working solution, one commits the new problem and solution to memory as a new "case" to which to refer in later instances of case-based reasoning.

Almost all people tend to use case-based reasoning to solve a wide range of problems in their day-to-day lives. Some professions in particular demand frequent use of such reasoning methods. Lawyers and judges, for instance, often base their arguments and decisions on previous similar legal cases. Mathematicians and students of mathematics use case-based reasoning when solving new and unfamiliar math problems. Almost all careers that require problem solving will require the use of such methods of reasoning at some point.

Discussion Comments


@miriam98 - Sometimes on TV I’ll watch a science show about a subject like dark matter or black holes or quantum mechanics. I only watch the shows that make the science simple for the lay person. I’m not a scientist myself.

Anyway, I like watching stories unfold about how different scientists try to tackle a problem that had been unsolved; usually these scientists will point to some past work or hypothesis and use that as the basis for their study.

At other times, they’ll throw out the old paradigms and try something new. But even then, the “new” approach comes from somewhere else; it’s not created out of whole cloth. Perhaps it’s another discipline or something that sheds some light on how to solve the current problem.

In either case, the drama unfolds like a mystery, until the scientist stumbles upon the solution. It’s fascinating to watch, and an instructive lesson in problem solving.


@miriam98 - I agree. Case based reasoning is also used a lot in court decisions, as the article points out. The operative code word there is “precedent.”

When it comes to federal and Supreme Court justices, it’s constantly a political battle when it comes to judicial appointments. That’s because a lot is on the line and that’s why the senators interrogate the nominees.

Will the new justice respect precedent? Will they overturn precedent? It’s a tricky balancing act, because during the confirmation process, the nominee is not supposed to tip their hat and show how they would rule.

Of course justices rarely overturn precedent, but there’s nothing to guarantee that they won’t. So I understand why there is so much contention, especially on controversial hot button social issues.


I love innovation in technology. It is one area where I think case based reasoning is used extensively. Sometimes the old paradigms work; at other times, they don’t work, but other paradigms not previously considered as relevant do work.

It’s called thinking outside the box in that case. Take the so-called PC wars between Microsoft and Apple for example, especially in the early days.

During that time, the emphasis was on hardware. Apple was winning on that front. But Microsoft had a different take; make the hardware generic, and focus on the operating system. Microsoft used the graphical operating system concept that they had seen used by Xerox and modeled that to Windows.

Eventually Microsoft won against Apple on that front, at least in terms of market share. I’m not arguing that one is better than the other. That’s just an example I’m using.

Post your comments
Forgot password?
    • Judges often base their decisions on previous similar legal cases.
      By: Andrey Burmakin
      Judges often base their decisions on previous similar legal cases.