Design Workflow (policies & capacity, classes of service)
This domain tests whether you can turn a workflow into an explicit, capacity-aware, policy-driven system: columns that describe states of work, WIP limits grounded in real capability, and classes of service that decide what gets pulled next.
Model the workflow as states
Columns are states of work, not people or job titles. Give each state an entry and exit criterion so a card's position is truthful; name the work item types you handle.
Make policies explicit
Definition of ready and done, pull criteria, WIP limits, blocked-work policy, prioritisation rules, capacity allocation - written where the team can see them. A policy held only in someone's head cannot be inspected or improved.
Capacity before optimism
Derive capability from data: throughput per week, effort per item, availability of scarce specialists. Set WIP limits from that analysis; Little's Law relates the three quantities: average WIP = throughput × average lead time. Reserve capacity deliberately - an expedite slot kept empty, a percentage held for maintenance work.
Classes of service
- Standard: first in, first out, no special treatment.
- Expedite: immediate attention, strictly capped, consumes reserved capacity.
- Fixed Date: must start by a calculated date; uses a lead-time buffer and is escalated when at risk.
- Intangible: valuable but not urgent (technical debt, options), protected by allocated capacity.
Worked example
Throughput is 12 items per week and average WIP is 14, so Little's Law gives an average lead time of about 1.2 weeks. Leadership asks for a three-working-day lead time (0.6 weeks): target WIP ≈ 12 × 0.6 ≈ 7. The team sets limits summing to seven across active states and keeps one further slot in reserve for expedite. If limits cannot be met, the honest answer is that the requested lead time needs lower demand or more capability - not more optimism.
Traps that cost marks
- WIP limits per person rather than per state.
- Unlimited expediting, which quietly removes every limit.
- Capacity allocation agreed once and never revisited.