The most important quality of software

What is the most important quality of software?

Correctness, they say.

And what is the second most important quality of software?

Readability, they say.

That is right, but only in theory.

(Useful pre-reading: About these papers)

If it was possible to write software just once, and never touch it again, then indeed, the most important thing, perhaps the only important thing, would be correctness. But in practice, this never happens. 

In the real world, requirements change, execution environments change, interfaces change. When that happens, we have software which used to be correct, but it is not correct anymore, and needs to be fixed to make it correct.

However, in order to fix software you have to be able to read it.

Thus, in practice, readability is a prerequisite for correctness, which brings us to the astounding realization that readability is even more important than correctness.

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Cover image by Fotis Fotopoulos on Unsplash