The Biggest Bug Is Not Understanding the Business

Not long ago, I heard a developer say: “I don’t want to know about business rules; I’m concerned with my code.” Setting aside the astonishment at the obvious lack of understanding of the connection between the chicken and the egg, this attitude also assumes a flawless translation between business rules and software requirements—something that, in practice, is as rare as it is impractical. This bias is the root cause of extremely complex bugs that typically cause cascading impact, require refactoring, and ultimately result in losses of schedule, reputation, and revenue.

One of the ways I like to define the goals of Quality in software development is “ensuring the persistence of business rules.” Of course, this is not the only persistence that matters, but if we are to prioritize the dimensions of conformance we must address, this certainly comes first. In other words, ensuring that the application actually solves the real-world problems that led to its development in the first place.

Super colorful discovery phases, fluid refinements, lean and scalable architectures, modern and intuitive design systems, well-established governance, and AI tools are of no use if your application does not meet business rules. This means that it is not enough to look only at form — which, at the limit, is exactly what the developer I mentioned does; it is necessary to look at content. This need for “more semantics and less syntax” runs through the entire software development process and translates, including according to ISTQB standards, into domain knowledge.

Domain knowledge is more than functional knowledge (since functionality already presupposes a level of implementation abstraction, even in high-level artifacts); domain knowledge is knowledge of the business. This translates into the need for all actors involved in a software development project to have adequate knowledge of the specific industry that the application being developed serves.

This is not merely field perception; for example, an empirical study (*) involving 232 globally distributed projects demonstrated that integrating business domain knowledge with technical knowledge produces:

• Improved design effectiveness
• A statistically significant reduction in defect density across all phases
• Greater alignment between delivered software and customer needs

In addition, there is the well-documented exponential increase in the cost of finding bugs later in the software development process (which is directly connected to domain knowledge issues): the IBM Systems Sciences Institute’s “Rule of 100” is one of the most cited references on this topic, showing that the cost of quality increases by an order of magnitude at each phase, from design and requirements mapping through production/post-release.

So how do we ensure the persistence of business rules, domain knowledge, functional proficiency, and, above all, how do we avoid the stance of the developer mentioned above? Software Quality Engineering offers several tools and processes that can support this path, but the first step is always recognizing this problem by everyone involved — especially decision-makers — so as to support investments, technical proposals, roadmaps, and team profiles that prioritize the constant pursuit of conformance.

Source: “An empirical study of the effect of knowledge integration on software development performance”, ScienceDirect (https://www.sciencedirect.com/science/article/abs/pii/S0950584904000618).