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Digital Products & Software Engineering Principles

Warning

These principles are not yet approved by the DHCW TDA

Introduction

These principles guide the design, development, delivery, and lifecycle management of digital products and software. They operate within the framework set by the overarching Architecture Principles and aim to ensure that our digital solutions are valuable, user-focused, high-quality, sustainable, and aligned with strategic objectives.

Deliver Measurable Value Continuously

Digital products and software must demonstrably meet user needs and organisational strategic objectives. Development efforts should prioritise features that deliver the highest value, released iteratively to enable rapid feedback and adaptation.

Rationale

Focusing on continuous value delivery ensures that resources are applied effectively, benefits are realised sooner, and products evolve in line with changing requirements and priorities within the dynamic health and care landscape.

Implications
  • Adopt agile and lean methodologies (e.g., Scrum, Kanban) for product development and delivery.
  • Define clear value propositions, key performance indicators (KPIs), and success metrics for all digital initiatives.
  • Prioritise backlogs based on value, risk, learning opportunities, and dependencies.
  • Embrace frequent, small, and incremental releases to gather feedback and deliver value early.
  • Establish robust feedback loops with users, clinicians, and stakeholders throughout the product lifecycle.
  • Product roadmaps are living documents, regularly reviewed and adjusted based on feedback and value realisation.

User Needs Drive Product Evolution

The ongoing development and evolution of digital products must be guided by a deep and empathetic understanding of user needs, behaviours, workflows, and feedback within the specific context of health and care in Wales.

Rationale

While (User-Centred Design principles](../user-centred-design/index.md) focus on the how of designing for users, this principle emphasises that what we build and how it evolves is continuously validated against real user requirements to ensure fitness for purpose and positive impact on health and care outcomes.

Implications
  • Integrate user research (e.g., interviews, observations, surveys) and usability testing as continuous activities throughout the product lifecycle.
  • Develop and maintain clear user personas, user stories, and journey maps relevant to Welsh health and care pathways.
  • Utilise data analytics and user feedback mechanisms to understand user behaviour, identify pain points, and measure satisfaction.
  • Product backlogs and feature development are directly informed and prioritised by validated user needs and evidence from diverse user groups.
  • Ensure services are simple to use, accessible, and inclusive, meeting relevant standards and supporting both Welsh and English languages.

Engineer for Quality, Resilience, and Maintainability

Software must be robust, secure, performant, and easy to maintain and evolve over its lifecycle to ensure long-term viability, minimise technical debt, and reduce the total cost of ownership, which is especially critical for systems supporting health and care services.

Rationale

High-quality engineering practices lead to more reliable, secure, and adaptable systems that can better respond to future needs without excessive rework or risk.

Implications
  • Adhere to approved coding standards, architectural patterns, and software development best practices.
  • Implement comprehensive and automated testing strategies, including unit, integration, contract, performance, and security testing.
  • Conduct regular, constructive code reviews and proactive refactoring to improve code quality and manage technical debt.
  • Design for modularity, loose coupling, and high cohesion to facilitate independent development, deployment, and scalability of components.
  • Embed security considerations throughout the software development lifecycle (DevSecOps), aligning with Security & Identity principles.
  • Apply rigorous clinical risk management throughout the software lifecycle for any product with potential clinical impact, adhering to relevant clinical safety standards and regulatory requirements.
  • Ensure systems are designed for observability (comprehensive logging, monitoring, tracing, and alerting) to support operational stability and rapid issue resolution.
  • Strive for resource-efficient software design and implementation to minimise environmental impact, aligning with sustainability goals.
  • Document software architecture and design decisions clearly and keep documentation up-to-date.

Embrace Agile and DevOps Culture and Practices

Foster a collaborative, communicative, and continuously improving culture, supported by DevOps practices, to enable rapid, reliable, and sustainable delivery of high-quality digital products and software.

Rationale

An agile and DevOps approach breaks down silos, improves flow, automates processes, and empowers teams, leading to faster delivery cycles, higher quality, increased innovation, and better responsiveness to evolving needs.

Implications
  • Promote the formation of empowered, cross-functional teams with shared ownership and accountability.
  • Implement robust CI/CD pipelines to automate build, testing, and deployment processes.
  • Encourage open communication, knowledge sharing, and collaborative problem-solving within and between teams.
  • Leverage endorsed collaboration tools and platforms to enhance teamwork and knowledge sharing, in alignment with Digital Workplace principles where applicable.
  • Adopt "you build it, you run it" philosophies where appropriate, with teams taking responsibility for the operational support of their services.
  • Conduct regular retrospectives and experiments to continuously learn, adapt, and improve processes, tools, and team practices.
  • Champion psychological safety to encourage experimentation and learning from failures.

Leverage Reusability and Promote Interoperability

Maximise efficiency, consistency, and integration capabilities by identifying, creating, and utilising common components, services, platforms, and data standards. Design systems to interoperate seamlessly within the ecosystem and with authorised external systems.

Rationale

Reusability reduces duplication of effort, accelerates delivery, and lowers costs. Interoperability is fundamental for a connected health and care system, enabling data to flow securely and efficiently where it's needed.

Implications
  • Prioritise the use of existing approved platforms, APIs, shared services, and common libraries.
  • Develop new components and services with reusability and clear interface contracts (e.g. APIs) in mind.
  • Adhere to established national and international interoperability standards relevant to health and care (e.g., HL7 FHIR, openEHR where appropriate).
  • Maintain and contribute to a catalogue of reusable assets, APIs, and data models.
  • Employ API-first design strategies to facilitate integration and enable a composable enterprise.
  • Ensure data is exchanged using agreed-upon formats and semantics, aligning with Data & Analytics principles.

Make Data-Informed Product and Technical Decisions

Product strategies, feature prioritisation, architectural choices, and engineering improvements should be guided by objective data and evidence, rather than solely by assumptions or opinions.

Rationale

Using data to inform decisions reduces risk, helps to validate hypotheses, optimises resource allocation, and ensures that efforts are focused on areas that will yield the most significant impact for users.

Implications
  • Instrument applications and systems to collect relevant operational data, user analytics, and performance metrics.
  • Establish and monitor Key Performance Indicators (KPIs) and Service Level Objectives (SLOs) for digital products and services.
  • Regularly analyze collected data to identify trends, insights, user behaviours, system bottlenecks, and areas for improvement.
  • Utilize A/B testing, canary releases, and other experimentation techniques to validate changes and guide product evolution where appropriate.
  • Ensure that data used for decision-making is accurate, timely, and relevant, and that its collection and use comply with data privacy and governance policies.

Manage Technology Pragmatically and Sustainably

Technology choices must be driven by fitness for purpose, long-term sustainability, alignment with the strategic technology roadmap, security requirements, and total cost of ownership, rather than by novelty or individual preference.

Rationale

Pragmatic technology management ensures that we invest in solutions that are supportable, scalable, secure, and cost-effective over their intended lifespan, minimising risks associated with obsolescence or niche skill dependencies, and aligning with overarching Architecture Principles.

Implications
  • Follow a "reuse before buy, buy before build" approach: prioritise reusing existing or publicly available solutions (including open source with appropriate support), then consider acquiring commercial off-the-shelf products, before commissioning new bespoke development, as guided by Architecture Principles.
  • Evaluate technologies using clear criteria, including maturity, community/vendor support, security posture, scalability, performance, interoperability, skills availability, and alignment with existing technology stacks.
  • Favor proven technologies, open standards, and solutions that align with the Cloud & Infrastructure principles.
  • Proactively manage technical debt: identify, prioritise, and address it systematically.
  • Consider the full lifecycle implications of technology choices, including development, deployment, operations, maintenance, and eventual decommissioning.
  • Maintain a clear technology radar and roadmap, regularly reviewing and updating it based on our evolving needs and the technology landscape.
  • Ensure that skills and knowledge for chosen technologies are developed and maintained.