Design principles like Open-Closed Principle, Liskov Substitution Principle, etc. are said to be important. But are they really? We asked 104 practitioners and scientists for their optinion on the importance of selected object-oriented design principles.


In this survey we aimed at identifying which design principles are considered to be important in practice. The survey was completed by 104 participants from different application domains and from companies of different size worldwide. The final ranking shows the design principles in descending order of importance.

Importance of design principles

Importance of object-oriented design-principles in descending order

Additionally three principles we did not explicitely ask for were considered to be important by the participants of the survey:

  1. Dependency Inversion Principle
  2. KISS (Keep It Simple and Stupid) Principle
  3. YAGNI (You Ain’t Gonna Need It) Principle

A summary of the survey results can be downloaded here. For further information contact Reinhold Plösch.

This survey was conducted in the context of the Object-Oriented Design Quality project.