> For the complete documentation index, see [llms.txt](https://jeyabalajis.gitbook.io/simple-rule-engine/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jeyabalajis.gitbook.io/simple-rule-engine/why-simple-rule-engine.md).

# Why Simple Rule Engine?

Decision-making has always been at the heart of any business. In certain industries (such as Lending), some of the decisions made are so dynamic & in flux that programming these decisions by hand is counter-productive.

Take the example of the decision to give someone a loan. It primarily involves ascertaining two fundamental factors:

* Ability to repay the loan.
* Intent to repay the loan.

When you start assessing a borrower based on the above, you typically get all facts required to make a decision (such as Bureau score, bank statements, etc.) and you will pass these facts through a decision matrix to arrive at

* A composite score on a scale that gives an indication of *whether the borrower will repay the loan* (**intent**)
* A recommendation of *how much loan* should be given to the borrower. (**ability**)

The aforementioned decisions involve the evaluation of multiple parameters. You cannot write a program to solve such complex scoring or decision problems:

* The evaluations and/or scores will *always* change over a period of time to adjust to business needs
* The *rules* will also vary based on the nature of the business product.

In the next section, let us look at some examples from Lending Industry which calls for a Rule Engine solution.

#### References

[Rules Engine by Martin Fowler](https://martinfowler.com/bliki/RulesEngine.html)