Employing a decision matrix: how the DfE selected a Kafka architecture
But figuring out the pros and cons of each prospective solution was only the start of the decision-making process. The DfE also had to carefully consider factors such as delivery timescale and risk. As a large government department, the DfE shouldered a responsibility to justify its technology implementation decisions. From start to finish, the department needed to display a clear and rational line of thought, researching and rating each architecture before recommending a final solution.
First, to formalise the process and minimise bias, Sion drew up a decision matrix. He’d evaluate each architecture on five core categories:
- How well it fits the DfE’s requirements
- How well it aligns with the DfE’s strategic vision and data over data strategy
- Whether its benefits balance out the drawbacks
- How rapidly and risk-free could it be rolled out within the department
- Whether the solution delivers enough value to justify its upfront cost
Measured trade-offs: analysing a data architecture’s value for cost
“Sion — Think twice before you assign a rating to the ‘value-for-money’ matrix box. With a platform-as-a-service solution, you’ll pay more on the front end to use the service…but you might spend less money overall. You’ve used fewer developer and vendor hours, and the solution is less likely to run into failure modes that cost time and money.”
For areas in which the solution was clearly subpar, he marked the spot with an X—Inadequate. If it seemed sufficient but not optimal, the solution secured a single check. If it exceeded expectations, he gave it two bold checks. At last, he ended up with a finished table filled with plus marks and minuses. As the matrix demonstrates, the APIs method had a good balance of technical pros and cons but would be difficult to scale, being more effectively applied to individual use cases. Meanwhile, the enterprise integration platform failed the ‘value-for-money’ test, and both the custom data pipelines and delivery risk were deemed overall too costly to roll out. Only one column displayed a line of light blue boxes and bold checks.