Weighted Decision Matrix for Smarter Architecture Decisions

Every architecture decision sets the system on a particular trajectory. For simple choices like selecting a code editor, personal preference or familiarity often works just fine. However, as the stakes rise, we need to work through all relevant factors in a more structured way.

What structured decision-making techniques empower us to tackle these complex decisions with confidence? Drumroll... introducing the weighted decision matrix. These are the benefits you can expect:

• Weigh options clearly and objectively.
• Eliminate guesswork and reduce bias.
• Consider all downstream effects before making a decision.
• Turn around uncertainty and reshape it into confident decision-making.
• Sift through the ambiguity when faced with several viable choices.

Let’s go over a hypothetical scenario where you decided to use the technique to compare a monolithic architecture with a distributed microservices approach, one step at a time:

1. Start by identifying and comparing the most critical factors that reflect your priorities and requirements, i.e., cost or complexity.
2. Not all factors matter equally, so assign higher weights to those most influencing the outcome. When growth is the priority, scalability often takes precedence over keeping expenses low.
3. Score factors on a scale from 1 to 10 for each option.
4. Multiply each score by its respective weight to figure out the total score for each factor.
5. Figure out the total score for each factor by multiplying each score by its respective weight.
6. Sum the results to determine the total score for each option. The choice with the highest total score should be the one.

The comparison shows that the microservices approach emerges as the better choice, with a total score of 33, narrowly surpassing the monolithic application, which scored 31.

Notably, even with cost in focus, microservices emerge as the approach that delivers the most value. Thanks to its scalability and team autonomy. As shown, these advantages win out over the drawbacks of increased complexity and higher upfront costs. If only it were that black and white. The monolithic approach might still be viable to stick with initially, with plans to transition to microservices later.

After completing the weighted decision matrix, you can use a stacked column chart to represent total scores in a different light. Represent each factor as a column and use color-coded segments to show the weight of each option. Layer them to clearly depict the cumulative totals.

DON’T:

• Use it for overly complex decisions.
• Be guided only by numbers.
• Assume all scores are accurate.
• Overweight certain factors.
• Neglect proper explanation.

All in all, the weighted decision matrix offers a reliable way to navigate uncertainty and avoid the pitfalls of making hasty decisions.

#ArchitectureDecisionMaking #SolutionArchitecture #WeightedDecisionMatrix