Quality, Developers and Testers: what is the best ratio?

In software development industry it is often discussed if it is necessary to have quality assurance on the projects. And what is the most effective presence of testing part in projects. In other words what is the most effective ratio of programmers and testers?

The ratio of programmers and testers can be different depending on a project. This doesn’t mean that large number of testers will provide their work effectively. The most effective average proportion is where a number of testers and developers is considered as 1 to 2.

In order to show this, let’s imagine a project with 4 developers working on it. For the best ratio of quality we should employ 2 testers.

When we don’t have testers on the project, only 10% of bugs can be found by programmers. When we were young and enthusiastic (but not as clever as today), starting our new project, we thought that well motivated and qualified programmers can provide their work in a best way.

But it’s obvious that everybody can make mistakes, and few programmers can find these mistakes.

If we have 2 testers they will approximately find 85% of bugs. Here is the rule that it is impossible to find 100% of bugs.

If we employ 3 testers they will find 90% of bugs, but their work won’t be effective and will cost more money. The price of each found error will be higher.

Thus, we will achieve the best ratio of efforts and the best quality if we have 2 testers and 4 programmers. Every additional tester will find some bugs but general price of his work is higher than effectiveness. Only on vitally important projects such as healthcare and financial projects this ineffective (we say here ineffective meaning expensive) work should be applied, because potential defect can be very expensive.

The same situation comes up when we talk of the time spent on a bug search: if we spend too much time on testing, it will become ineffective.

So, the task of testing is very important in the context of software development. We understand that the ideal ratio of testers and programmers can be applied only to the average projects. But the main idea is that the cost of the quality assurance may take up to 50 percent of software development cost.


Do you have any ideas about this problem?

Uhhh

I would be fired immediately.

Point is that if you are good developer you will not make 67046389215648309265483926 bugs.

Let's say you make 30 000 lines project. If you make more than 2 critical bugs , or more than 10 major than something is wrong.

OMHO on 10 developers 1 tester is more than enough (good tester).

Of course there is special cases where you will need 10 or more testers per 1 developer like for example with some complicated and critical calculations.

I partly agree with you!
But in fact all big software development companies have quality assurance department, do you realy think that they waste their money?

Please keep you blog posts in your blog.

Reported.

Why are you so negative to me?

Because we don't like people using our forums as a platform for advertising themselves and their own sites.

Your blog doesn't get enough hits? Why not find a forum with more hits and republish! Eventually you'll be able to make a signature with a direct link to your own site and thereby get more throughput.

Yeah... not gonna happen here.

Thread closed.