AndersenSoft
09-09-09, 07:03 PM
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.
read more you can here: Andersen blog. Software development company blog. (http://www.andersensoft.com/en/article_ratio.php)
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.
read more you can here: Andersen blog. Software development company blog. (http://www.andersensoft.com/en/article_ratio.php)