Chapter three (Agile Principles) in my Essential Scrum book describes the agile principles that underlie Scrum and compares them with those of traditional, plan-driven, sequential product development. Many people have asked me to share the summary comparison table at the end of that Chapter. It is reproduced below. Free to comment on it!
| Topics | Plan-Driven Principles | Agile Principles |
|---|---|---|
| Similarity between development and manufacturing | Both follow a defined process. | Development isn’t manufacturing; development creates the recipe for the product. |
| Process structure | Development is phase-based and sequential. | Development should be iterative and incremental. |
| Degree of process and product variability | Try to eliminate process and product variability. | Leverage variability through inspection, adaptation, and transparency. |
| Uncertainty management | Eliminate end uncertainty first, and then means uncertainty. | Reduce uncertainties simultaneously. |
| Decision making | Make each decision in its proper phase. | Keep options open. |
| Getting it right the first time | Assumes we have all of the correct information up front to create the requirements and plans. | We can’t get it right up front. |
| Exploration versus exploitation | Exploit what is currently known and predict what isn’t known. | Favor an adaptive, exploratory approach. |
| Change/emergence | Change is disruptive to plans and expensive, so it should be avoided. | Embrace change in an economically sensible way. |
| Predictive versus adaptive | The process is highly predictive. | Balance predictive up-front work with adaptive just-in-time work. |
| Assumptions (unvalidated knowledge) | The process is tolerant of long-lived assumptions. | Validate important assumptions fast. |
| Feedback | Critical learning occurs on one major analyze-design-code-test loop. | Leverage multiple concurrent learning loops. |
| Fast feedback | The process is tolerant of late learning. | Organize workflow for fast feedback. |
| Batch size (how much work is completed before the next activity can start) | Batches are large, frequently 100%—all before any. Economies of scale should apply. | Use smaller, economically sensible batch sizes. |
| Inventory/work in process (WIP) | Inventory isn’t part of the belief system so is not a focus. | Recognize inventory and manage it to achieve good flow. |
| People versus work waste | Allocate people to achieve high levels of utilization. | Focus on idle work, not idle workers. |
| Cost of delay | Cost of delay is rarely considered. | Always consider cost of delay. |
| Conformance to plan | Conformance is considered a primary means of achieving a good result. | Adapt and replan rather than conform to a plan. |
| Progress | Demonstrate progress by progressing through stages or phases. | Measure progress by validating working assets. |
| Centricity | Process-centric—follow the process. | Value-centric—deliver the value. |
| Speed | Follow the process; do things right the first time and go fast. | Go fast but never hurry. |
| When we get high quality | Quality comes at the end, after an extensive test-and-fix phase. | Build quality in from the beginning. |
| Formality (ceremony) | Formality (well-defined procedures and checkpoints) is important to effective execution. | Employ minimally sufficient ceremony. |