I'm in the habit of putting a motivating quote on the top of each of my syllabi. For my introductory programming course, I'd like to focus the class on the theme of testing and verification. Of course, this is also an important theme in non-CS disciplines, as well.

So I'd like to find the best possible short, positive (not sarcastic or negative), informative quote on the issue of testing and verification. Ideally this would be from someone fairly well-known or influential in the CS field, but that's not necessary. Web searches for this tend to dredge up pages on automatic testing suites and the like, so I'm hoping that someone here knows of a good one.

What is the best motivating quotation on the importance of testing, checking, and verification for freshmen college (STEM) students?

  • "Best" is completely opinion-based and we don't take questions about specific subjects. Feb 14, 2017 at 10:25
  • 2
    I'm voting to close this question as off-topic because it is about software engineering and its teaching, not about life in academia.
    – xLeitix
    Feb 14, 2017 at 10:30
  • Can someone suggest a more appropriate SE site for this question? Feb 14, 2017 at 14:51

2 Answers 2


Program testing can be a very effective way to show the presence of bugs, but is hopelessly inadequate for showing their absence.

Edsger W. Dijkstra


Testing by itself does not improve software quality. Test results are an indicator of quality, but in and of themselves, they don’t improve it. Trying to improve software quality by increasing the amount of testing is like trying to lose weight by weighing yourself more often. What you eat before you step onto the scale determines how much you will weigh, and the software development techniques you use determine how many errors testing will find. If you want to lose weight, don’t buy a new scale; change your diet. If you want to improve your software, don’t test more; develop better.

Steve McConnell in Code Complete

  • Unfortunately, I feel like this is not a positive statement on the subject of verification, et. al. It's mostly a lot of "not"s and "don't"s. Feb 14, 2017 at 8:03

Not the answer you're looking for? Browse other questions tagged .