Artur Södler Software-Qualität
What is Quality?
|DIN EN ISO 8402:1995-08:||"The entirety of attributes of a unit as to its suitability to comply with predetermined and implied requirements"|
|EN ISO 9000:2005:||"Level of compliancy of a set of inherent attributes with its requirements"|
|commonly in Japan:||customer satisfaction|
We have vast difficulties to define quality. After all, the European Standard EN acknowledges the fact that only measurable attributes can be quantified. Merely the deduction is missing, that we are badly in need of measurability.
There is another interesting point of view:
Quality is, if you are happy and content with your life. For that purpose, the assessed software must contribute: a) The software gets paid for, and therewith you buy a sailing boat. b) Your customer is happy, und you feel content to be the reason of it.
The rating depends on whether you are more interested in a sailing boat or in a smile on your customer's face. You may counter using strict logic: "The smile on my customer's face is disappearing quite fast. That and a dollar will get me a cup of coffee." But please bear in mind that the customer recommends your product.
However, in order to make your customer smile and pay, he himself must become happy and content, which leads us inevitably back to definitions like that of the European Standard. Let us start by reading between the lines:
|•||Without requirements there is no quality. So much for the necessity of requirement specifications. Unfortunately that includes those requirements that we carry about in our minds.|
What cannot be quantified, is not part of quality. A serious misbelief. The number of crashes at the customer's site could be quantified if only we simply would start counting.
|•||The goal is: 100% of requirements. Each and every difference is considered to be an "error" oder "insufficiency". First of all, we can only do things wrong, there seems to be no reward for correct code.|
The last one resembles to the Swabian saying: "Nicht gescholten ist halb gelobt." (Not reproached is halfway approved.) Swabians supposedly can only criticize. If they don't, it is their kind of approval.
One trick is to turn the tables: If the software calls the customer's attention to the fact it did work and how well it worked, it may leave a mark. Now the difference between the European Standard and the Japanese definition becomes evident: In the Japanese definition, marketing is part of quality. What do you think: Do the Japanese have a point?