Artur Södler Software-Qualität

Under which circumstances is more quality worth while?

If someone is interested in this subject, his shoe pinches. Often it gets so far that current projects and developments are seriously delayed by the backlog of maintenance and repair, and customers tend to pull out.

Deadlines are altered to vague promises, constantly shifted. Managers overwillingly give in to the temptation to deliver a Potemkin village, that, for a start, quickly satisfies the customers' most urgent needs. Tom DeMarco describes this state in his book "The Deadline" most precise and dissuasive.

Have a look at the following theses:

•		Tight deadlines downgrade quality.
•		Sketchy and repaired is more laborious than thorough in the first place.
•		The cost of adjustments is hardly planable. Necessary adjustments are rarely included in the planning.
•		Unplanned incidents mess up the timetable.

Did you see the point? It is a vicious circle, similar to a spiral of debt. If you have ever got so far, then interests, arrears fees and enforcement charges burn a hole in your pocket. In the same manner the backlog of maintenance and repair must be looked at: It is a debt, which must be paid back, can overwhelm us, and should be listed on the balance sheet.

The contrary is to be preferred. The minimum requirements are:

•		Ongoing amendments do not menace new deadlines.
•		The unnecessary additional cost by amendments is less than the unnecessary additional cost by work done overthoroughly in the first place.

Not only amendments mean additional cost (accepting the complaint, error diagnostics, adjustment, software build, delivery, correction of erroneous data etc.), but also diligence in development. Too much diligence costs, too.

It is not about simply balancing these two. In fact it is about favoring quality as far as your customer rewards you by money and recommendations.

In practice there is a certain degree of demerit which is acceptable for a software. This degree is based on customers' expectations: If in general everything works well, we readily excuse the word processing software to underline the name of our contact person (let us say Mr Walpole) as a spelling mistake with a red curl. But if the last two pages are missing from time to time because of a software crash, things get nasty. Is the crash due to lack of memory, then the software is of a quality customary in the market. Go ahead and classify your products:

Bad Quality	The software installation fails depending on the preinstalled environment without any notice. The software does generally not comply with the requirements. Important functions are missing, results are not reproducable. Triggering a function does not give a feedback, the user is unaware of whether the application is still working or not. Sometimes a saved document cannot be read again, or it contains an irreversible error. Users are frustrated and confront you with errors and claims, the hotline is parrying. Recommendations come out negatively.
Quality Customary in the Market	The software installation checks requirements, but fails depending on the preinstalled environment without any notice and uninstalls completely. On the home page of the manufacturer there are installation FAQ giving hints to possible reasons. The software generally complies with the requirements. Many extensions make the system somewhat confusing. In a lack of resource situation there is for instance a message box without content. Very rare crashes with data loss. Confronted with a complaint, the hotline primarily directs the customer to a charged successor version. In spite of a certain discontentedness, the product is recommended — if there is no better product on the market.
Expected Quality	The software installation checks requirements, but fails depending on the preinstalled environment with a detailed meaningful notice and uninstalls completely. The software complies with the requirements. The many extensions to the software are well-organized. In a lack of resource situation there is for instance a message box without content. No crashes, no data loss. Confronted with a complaint, the hotline directs the customer to a charged successor version in the first place, but older versions are also adjusted. Very old versions fall through the cracks. The customers readily use updates at a reasonable fee. The product persists at the market despite of competing software.
High Quality	The software installation checks requirements, displays the individual steps of the installation, but stops with a detailed meaningful notice. You may choose to either yet create the necessary prerequistes or make the software uninstall itself completely. The software complies with the requirements without restrictions and produces always quickly reproducable results. The functionality does not exist of many extensions but is intrinsically organized. Resources needed for error handling have been allocated at the beginning, error messages are precise and describe the cause and possible remedies. Processing units are designed modular and comprehensible. The software contains — generally hidden to the customer — many checks for limits and plausibility. errors do not spread and do not lead to subsequent faults. Some customers are so positive about the product that they actively promote it.