A class of service is a policy for how to treat the work
Think of a café. A regular coffee waits its turn (Standard). A catering order has a pickup time (Fixed delivery date). A spilled, scalding-coffee emergency jumps the queue (Expedite). And "wipe that table when you get a sec" happens only when there is slack (Intangible). Four classes of service, one café.
The four classes and the cost they protect
Each class maps to a cost-of-delay shape, how the value of finishing changes over time, which is what makes the policy more than a label.
| Class | Cost-of-delay shape | How the team treats it |
|---|---|---|
| Standard | Rises, then levels off | Pull in order, FIFO. No queue-jumping. Most healthy work is Standard. |
| Fixed delivery date | Steady, then a cliff on the date | Protect the date; the class requires a due date. |
| Expedite | High and steep from right now | Drop almost everything, one at a time. |
| Intangible | Low now, may spike later | Slack-fill; escalate when the curve turns up. |
Most work that feels urgent turns out to be Standard, which frees real capacity for the rare item that genuinely cannot wait.
Class, card type, and workflow are different things
These are orthogonal, so the same Bug can be Expedite today and Standard next week. Card type says what the work is. Class of service says how urgent it is and what shape its cost takes. Workflow says the path it follows. Collapsing them is what makes a board look tidy while the real expectations stay muddy.
Make the policy real with WIP and allocation
- WIP limit per class caps multitasking. For Expedite it is the one-emergency-at-a-time rule (WIP = 1).
- WIP allocation reserves capacity, for example 20% for Intangible so debt actually gets paid down.
- Priority rank drives the prioritize sort: Expedite → Fixed delivery date → Standard → Intangible.
- The default class is Standard, so promoting work to a higher class is always a deliberate act.
From class to economics
Assigning a class also gives the work its economic shape. ScrumDo seeds each class with a default cost-of-delay curve, so a card inherits its economics for free and a planner only overrides with better evidence. To see how that shape becomes a number you can sequence by, read the Cost of Delay guide.
Key terms
- Standard
- The FIFO default. Most work belongs here; its value rises then levels off.
- Fixed delivery date
- A hard date drives the work. Protect the date; the class requires a due date.
- Expedite
- Drop almost everything and finish it one at a time (WIP = 1). Value is high and steep from now.
- Intangible
- Slack-fill work whose cost is mostly latent risk that can spike later.