WSJF Explained: Weighted Shortest Job First

WSJF, or weighted shortest job first, is a way to order work so you deliver the most value in the least time. You estimate each item's cost of delay, divide it by its size and do the highest scores first.

It's built on a simple truth. When work queues for the same team, every week you spend on one item is a week the others aren't earning.

The Origins of WSJF

The idea comes from Donald Reinertsen's work on product development flow, where he showed that dividing cost of delay by duration minimises the total cost of waiting. The Scaled Agile Framework, SAFe, later popularised a version called WSJF that uses relative scores instead of money.

How WSJF Works

In the SAFe version, cost of delay is the sum of three relative scores:

• Business value. How much value will this create for users or the business?
• Time criticality. Does value fall away if we wait? Is there a fixed date?
• Risk reduction or opportunity enablement. Does it reduce a risk or open up future options?

Each is scored with a modified Fibonacci scale such as 1, 2, 3, 5, 8, 13 and 20. You then divide the total by job size, scored on the same scale. The result is the WSJF score.

WSJF, Cost of Delay and CD3

These three are close relatives, and it helps to know which is which.

• Cost of Delay puts a value on waiting, ideally in money per week.
• CD3, cost of delay divided by duration, uses that money figure and the real duration to give a score.
• WSJF follows the same logic but uses relative points for both parts.

If you can estimate money, CD3 is sharper. If you can't, or you're comparing very different kinds of work across many teams, WSJF's relative scores are a practical alternative.

When to Choose WSJF

Choose WSJF when you need to sequence a large backlog using relative scores rather than money. It's common in portfolio and programme planning, where many items compete for the same teams.

It's not a tool for deciding whether work is worth doing at all. It only tells you the order.

How to Use WSJF, Step by Step

1. List the items competing for the same team or group of teams.
2. Score business value for every item, one column at a time. Start by finding the smallest and giving it a 1.
3. Score time criticality in the same way.
4. Score risk reduction or opportunity enablement.
5. Add the three scores to get the cost of delay.
6. Score job size relative to the other items.
7. Divide cost of delay by job size and order the work by the result. Talk about anything that surprises you.

Scoring one column at a time across all items matters. It keeps comparisons honest.

A Worked Example

A building society's digital team has four items waiting.

Item	Value	Time	Risk	Cost of delay	Size	WSJF
New savings account rates page	8	13	2	23	3	7.7
Mortgage calculator refresh	5	2	1	8	5	1.6
Fraud alert improvements	13	8	13	34	8	4.3
Branch finder redesign	3	1	1	5	2	2.5

The fraud work had the biggest cost of delay. Yet the rates page goes first, because it's urgent and small. Fraud alerts come second. The mortgage calculator, which the loudest stakeholder wanted, comes last.

Avoiding Scoring Theatre

WSJF can easily become a ritual where people argue about numbers and nobody changes their mind. A few habits keep it useful.

Keep the group small and informed. The people scoring should understand the customers, the business and the work. A crowded room tends to defer to the most senior voice.

Anchor each column first. Find the smallest item in a column and give it a 1. Everything else is scored relative to it. This keeps the scale honest and stops inflation over time.

Reveal scores together. If people call out numbers in turn, the first number sets the tone. Writing scores down privately, then revealing them, gives you a truer picture.

Spend time on the outliers, not the averages. When one person gives a 13 and another gives a 2, there's something important to learn. Often one of them knows about a deadline, a risk or a customer the others don't.

Finally, use the ranking to start a conversation, not end one. If the top item feels wrong to the team, look again at its inputs before you commit. The aim is a better order of work, not a perfect spreadsheet.

Common Mistakes

• Arguing over decimal points. WSJF is for spotting big differences, not ranking 4.3 against 4.1.
• Letting one voice set every score. Score as a group, and ask for reasons behind the outliers.
• Scoring row by row. Score each column across all items, so everything is compared like for like.
• Treating big items as untouchable. A low score often means the item should be split, not ignored.
• Using it to judge worth. WSJF orders work. It doesn't tell you if work should exist.

How WSJF Compares with Other Tools

WSJF and RICE both divide value by effort. RICE focuses on reach and confidence. WSJF focuses on urgency and risk.

WSJF and MoSCoW work at different levels. MoSCoW decides what's in a release. WSJF orders the work across releases.

One quiet benefit of WSJF is that it rewards small batches. Splitting a big job almost always raises its score, which nudges teams towards delivering value sooner.

The Product Field Kit includes a fillable WSJF worksheet and a calculator that scores and ranks your backlog as you type.

Questions People Ask

← More Field Notes