Visualisation plays a key role in determining requirements since it ensures that all of the stakeholders can understand the results. No complicated process management tools are required. Simple tools such as Excel and PowerPoint can be used to quickly obtain good results in determining requirements. Formulation of requirements is an important phase in software development. If the wrong course is taken here, the ensuing errors will not be discovered until late in the process. This situation is made worse by outsourcing of development work. If the requirements are not airtight in such projects, discrepancies and higher costs are inevitable. Experience has shown that when formulating requirements, it is important to choose a practical approach that suits the company’s organisation and available resources. Good results can then be obtained with surprisingly simple tools.
EXCEL – a professional tool for formulating requirements
An industrial company is preparing to purchase a tool to support its processes. As an initial step, 25 employees are trained in requirements management. From the participants in the three-day course, a core team is formed with eight members from different departments. They are involved in the end-to-end process for the corresponding product and are joined by an external coach. Since the company did not have any experienced interviewers, the typical approach involving an initial stage to determine the requirements through interviews was rejected. Instead, the expertise available in the core team was exploited in a targeted manner. One team member was a business process manager. With his help, the processes relevant to the new tool were modelled in workshops. Use cases were an important resource here. They could be used to specify the interactions between user and system as well as the necessary preconditions and the final result. Processes and use cases were visualised with Excel (see Fig. 1). Based on the use cases, it was then easy to derive the requirements. In this manner, the foundation needed for tool evaluation was laid.
Fig. 1: Simple process and use-case modelling in Excel
In this case, Excel turned out to be a suitable tool for multiple reasons. First, a clear and business-relevant representation of the processes was developed. This could also be printed out as it was expressed in a well-structured manner over several pages. Moreover, the collaborative formulation approach gradually clarified the scope and usage of the planned tool. Finally, Excel was available to all of the team members and no additional licence fees were incurred using it. Of course, Excel has its limits. For example, relationships between processes are practically impossible to represent. Accordingly, the program is suitable primarily for determining requirements in smaller projects such as the one described in Example 1. However, even when faced with significant complexity, a dedicated project management tool is not always necessary. In such cases, it is important above all to maintain an overview through suitable visualisation. This visualisation must be clear to all of the stakeholders. The business-relevant visualisation that is necessary can also be created satisfactorily with PowerPoint. Such presentations are frequently easier to understand than complex activity diagrams, for example.
EXCEL – an efficient tool for consolidating multiple requirements
An industrial company is developing a complex machine. The company has learned from past experience and intends to thoroughly formulate the requirements. The international product manager determines customer requirements and passes them on. At the same time, different departments in the company contribute their own requirements. As a third source, there are previously formulated requirements for a similar machine currently under development. In this manner, more than 400 requirements are collected. Once the requirements are gathered from the different sources, they must be consolidated in a second step. The goal is to obtain a complete and consistent list with no superfluous requirements. Consolidation was facilitated by business-relevant visualisation at the process level. In an initial step, the processes that the new machine was expected to support were compiled. This was based on customer requirements and the results obtained by the international project manager in cooperation with the requirements manager. The individual processes with their steps were presented in a clear manner using PowerPoint slides. Then, the requirements were mapped onto these visualisations of the processes (see Fig. 2).
Fig. 2: Example of a process overview in an error situation
However, some requirements could not be captured in this manner. They concerned prerequisites such as the presence of a power supply. These requirements were compiled and used in the creation of a system overview. This, in turn, was presented using PowerPoint and the requirements were attributed to the individual components (see Fig. 3).
Fig. 3: Overview with the actual system and individual interfaces
In workshops, the requirements were then cleaned up based on visualisation that was understood by everyone. Redundancies and contradictions were identified. The number of requirements dropped significantly but some gaps were also discovered at the same time which could still be resolved.
EXCEL and POWERPOINT - coherent visualisation of requirements
These two examples demonstrate that good results can be obtained in certain situations in requirements engineering using simple tools. The quality of the requirements is a function of whether the requirements are understood by all of the stakeholders (and not of the actual tool that is used). Under certain circumstances, the required understanding can be engendered more easily with Excel or PowerPoint than with many high-end products. Furthermore, these tools are easy to use and do not generate any additional expenses. Prior to using any specific tool, it is thus worth investigating whether there are simpler alternatives.