Rubber duck debugging

Rubber duck debugging (or rubberducking) is a debugging technique in software engineering. A programmer explains their code, step by step, in natural language - either aloud or in writing - to reveal mistakes and misunderstandings.

A rubber duck in use by a developer to aid debugging

The name is a reference to a story in the book The Pragmatic Programmer. It tells a story of a developer who carried a rubber duck who explained their code to it line by line.^[1] Variations of the practice use other objects or even pets; teddy bears are especially common.^[2][3]

Approach

Programmers often discover solutions while explaining a problem to someone else, even to people with no programming knowledge. Describing the code, and comparing to what it actually does, exposes inconsistencies.^[4] Explaining a subject also forces the programmer to look at it from new perspectives and can provide a deeper understanding.^[5]

The programmer explaining their solution to an inanimate object (such as a rubber duck) does not have to interrupt others. It also works better than thinking aloud without an audience.^[6] This approach has been taught in computer science and software engineering courses.^[7][8]

In popular culture

On 1 April 2018, Stack Exchange launched an April Fools' Day joke called Quack Overflow. A rubber duck avatar appeared in the bottom right corner of the screen, listened to user problems, and pretended to type solutions, only to respond with a simple "quack" sound. It referenced rubber ducking as a powerful method for solving problems.^[9]

See also

• Computer programming portal

• Code review
• Pair programming
• Socratic method
• Desk checking
• Duck test
• Duck typing
• Software walkthrough
• Eureka effect § The Aha! effect and scientific discovery
• Think aloud protocol
• Pointing and calling
• Rogerian method
• Worry dolls
• Learning by teaching
• Body doubling