Essentials of the Definition of Done in Hardware Product Development
Before delving into the Definition of Done (DoD), it’s essential to revisit some fundamental terms related to this topic.
Scrum: An Agile framework that employs short development cycles known as sprints, focusing on continuous improvement.
Backlog: A comprehensive list of tasks, ideas, and requirements that need to be addressed within a project. For example, in a smartwatch project, the backlog could include tasks such as “designing the case,” “choosing the display,” “creating the prototype,” and “testing for waterproofing.”
Definition of Ready (DoR): A set of criteria that defines when a task is prepared to commence. For the task “designing the case,” DoR might include having an approved initial design, the necessary tools and materials on hand, and alignment with the engineering team.
Sprint: A short, defined period (typically 2–4 weeks) during which the team focuses on a specific set of tasks. For instance, during a sprint, the team might work on “designing the case” and “choosing the display.”
Task: Specific activities carried out within a sprint. For the task “designing the case,” this could involve “sketching the case,” “creating a 3D model of the case,” and “conducting strength tests.”
User Story: A brief description of a feature or requirement from the end user’s perspective. User stories represent pieces of functionality that the team aims to complete within one sprint. For example, a user story in a smartwatch project could be, “As a user, I want the smartwatch to measure my pulse so I can monitor my health.”
Epic: A substantial, high-level task or initiative that typically breaks down into multiple user stories and tasks. Epics cover significant aspects of the product’s functionality and may span several sprints. In a smartwatch project, an epic might be “Develop a health monitoring system,” which would include smaller tasks like “Create a heart rate sensor,” “Integrate a pedometer,” and “Develop a data analysis app.”
Increment: A completed portion of work that can be integrated into the product and presented to stakeholders. Once the “case design” task is completed and verified, it is integrated into the smartwatch prototype for further testing.
Understanding the Definition of Done (DoD)
The Definition of Done (DoD) is a concept that emerged within the Agile methodology, widely used in project management. In Agile, projects are broken into short cycles (sprints), with each sprint requiring clarity on when a task or piece of work is truly complete. The Definition of Done (DoD) plays a critical role in this process.
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In hardware product development, the DoD is as crucial as in software development for several reasons:
Cost of changes: Manufacturing decisions are often irreversible and costly. For instance, if a printed circuit board (PCB) or device casing is fabricated with an error, correcting it involves rework and additional costs for new materials and production.
Complexity of fixes: Developing a medical device such as a pacemaker requires extensive safety and reliability testing, including various electrical safety checks like electrostatic discharge (ESD) tests and electromagnetic compatibility (EMC) tests. These assess the device’s resistance to external electromagnetic fields and its ability not to interfere with other devices. Fixing an error might necessitate remanufacturing the device. In contrast, web application development allows for quicker bug detection and resolution through automated tests and CI/CD (Continuous Integration/Continuous Deployment) systems.
Sequential and interdependent stages: In hardware development, design errors can affect all subsequent stages, necessitating rework not only of design drawings but also of already manufactured components. While errors in video game development can impact various modules, such dependencies are generally less severe, and fixes can often be made without overhauling all components.
Production and logistics requirements: Developing complex systems such as medical devices or aviation equipment requires the coordination of supply chains, assembly processes, logistics, and distribution. Each production stage must strictly adhere to quality and safety standards, increasing the complexity and time required to address errors. In contrast, software development, such as cloud services, allows for automated updates and quick fixes without the need for physical logistics.
Safety risks: Errors in developing a car control system (e.g., ABS) can lead to accidents and endanger the lives of drivers and passengers. Consequently, the DoD includes rigorous safety tests and checks. While errors in banking software development can lead to severe consequences like data breaches or financial losses, human lives are not at stake.
Definition of Done vs. Definition of Ready
Both the Definition of Ready (DoR) and the Definition of Done (DoD) are vital concepts in development, particularly in hardware products. Though they sound similar, they serve different purposes. The Definition of Ready establishes the conditions necessary for a task to begin, ensuring the task is prepared for execution. Meanwhile, the Definition of Done specifies when a task is fully completed, confirming that the work meets all standards and requirements. DoR is applied before starting a task and serves as a filter to check its readiness, while DoD is applied after a task is completed, evaluating the completeness of the work. DoR emphasizes preparation, including requirements, resources, availability, and task clarity, whereas DoD focuses on completion, encompassing testing, quality, documentation, and integration.
For example, in a project to develop a PCB for an IoT device, the task “Develop a control board for the temperature sensor” is ready to start (DoR) if there is a clear task description, requirements are defined, all components are available, acceptance criteria are approved, and the task is estimated to take 30 hours. It is considered done (DoD) when the board is designed and manufactured, all tests (functional, thermal) are completed, the board is verified to meet standards, documentation is updated, and the board is integrated into the device prototype.
