The Weighted Shortest Job First prioritisation technique, why you need it and how to do it

Weighted Shortest Job First is a prioritisation technique that provides a linear list of priorities with the optimal cost-to-value ratio; unlike the more famous MoSCoW technique which is more suited to setting a scope.

This cost-to-value ratio is great when you want to provide as much value to your customers as quickly as possible. It can also highlight when a planned work item is too large; if a work item that was expected to come near the top of the prioritisation has ended up low due to the cost of delivery then it can drive conversation into how that key work item may be broken down to highlight which parts of it are genuinely high value.

The calculation of Weighted Shortest Job First is the Cost of Delay which is based on 3 values (Business Value, Time Criticality and Risk Reduction/Opportunity Enablement) which are scored relatively using the Fibonacci sequence and added together. The Cost of Delay is then divided by the Job Size which is also scored relatively in Fibonacci. An example calculation for a work item would end up looking like (3 + 13 + 8) = 24 / 5 = 4.8, meaning the WSJF score for the work item is 4.8.

You may have noticed that I said all items are scored relatively and be wondering what that means. Scoring relatively means that the smallest value (1) and largest value (21) only represent the smallest and largest of that specific group of work items. A work item that scores 1 for Job Size may still take 3 months to deliver, it just means that all the other work items will be bigger than that smallest one.

Running a Weighted Shortest Job First workshop

Firstly that heading should really be pluralised because you’ll need to run two workshops; one with Business representatives to find the Cost of Delay and one with Delivery representatives to get the Job Size.

It is possible to get all of the values at the same time, especially if the Business and Delivery teams are extremely close; however in most organisations if you try to combine the sessions you’ll essentially be keeping a group of expensive people disengaged for one half of the workshop and a different group of expensive people for the other half, so quite a bit of wasted time across two different teams.

Goal of the workshops

For the Cost of Delay session: score all of the work items on Business Value, Time Criticality and Risk Reduction/Opportunity Enablement.

For the Delivery session: score all of the work items on Job Size.

Note: After both workshops are complete you will have some offline work to run the calculation for all of the work items that have been scored, this isn’t done in a workshop because it can take a little while to complete and watching you calculate the scores isn’t really the best use of most people’s time.

Time

1 Hour to 1 ? hour per 20 work items

Who to invite

To keep the workshops focussed you want to keep the list small and ensure that beforehand they have done the prework of understanding at a high level what each work item is so they are able to score everything and not derail the workshop with discussions about what each work item is.

For the Business session:

-????????? Product Management (who should have consulted Sales, Marketing, Legal, etc)

-????????? Product Owners

-????????? Project Management (as optional and only for awareness)

For the Delivery session:

-????????? Product Owners

-????????? Business Analysis (because analysis time counts toward the Job Size)

-????????? UI Design

-????????? Software Architecture

-????????? QA (aka Testing)

Required Equipment

Either a whiteboard/Post-it combination or an online whiteboard tool such as Mural/Miro.

Agenda for the Business session

1.?????? Introductions/what the session is about/goal of the session

2.?????? Business Value

3.?????? Time Criticality

4.?????? Risk Reduction/Opportunity Enablement

5.?????? Wrap up and next actions

Introduction

At the start of the session you will need explain Weighted Shortest Job First is and why it is being used. Initially you may find some resistance to this technique since it does take effort to get going so you’ll really need to sell the benefits to begin with. Then go on to explain the Fibonacci scoring system and how the work items will be scored relative to each other.

Business Value

The Business Value is looking at what monetary or reputational value the work item will bring to your organisation. After describing the Business Value reiterate how work items are scored relative to each other and that the score of 1 doesn’t mean something is totally worthless. Then begin by having the work item that scores a 1 identified and then the work item that scores 21. No other work items should be allowed to score a 1 or 21 but that is at your discretion as the facilitator.

Any time your attendees start discussing how urgently something is needed for regulatory reasons remind your attendees that the work items will be scored on this later. It is important that only the Business Value is being considered at this stage.

Time Criticality

Time Criticality is reasonably self-explanatory. How urgently is the work item required; considerations to include are customer commitments, beating competitors to market or similar.

As with the Business Value, it is important to repeat that the work items are being scored against each other. Also be careful that scores are being based solely on the Time Criticality and not taking any other factors into consideration.

Risk Reduction/Opportunity Enablement

This section is quite broad and some people will do it as two separate columns however I prefer to do the two together since we need to keep in mind how much time is being spent in the workshop vs the granularity of the scoring.

Risk Reduction is based on considerations such as security needs or covering the risk of losing a customer if the work item is not delivered.

Opportunity Enablement is great for technical enabler type work items to be given consideration. A work item that introduces functionality that would allow the Product to be sold to new customers would also score well here.

Since it’s a combined field, if a work item both reduces risk and creates an opportunity then it will score very highly, scoring high on just one factor would place it nearer the middle and low on both is low overall.

You may have already said this two or three times but do reiterate how work items are being scored against each other relatively.

Wrap up and Next actions

After completing the 3 prior sections you’ve now completed the Cost of Delay side of the Weighted Shortest Job First prioritisation. Be sure to thank your attendees for their patience, especially if this was the first time you’ve done this for the project. Let your attendees know that you’ll be moving on to do the Job Size session with the Job Size team and that once that has been done you will tally up the scores, produce the prioritised list and share it.

Agenda for the Delivery session

1.?????? Introductions/what the session is about/goal of the session

2.?????? Job Size

3.?????? Wrap up and next actions

Introduction

At the start of this second session you will need to largely repeat what you said at the start of the first one. So, introduce Weighted Shortest Job First, why you’re doing it and also how the scoring works.

Job Size

Job size, like all of the business scores, is scored relatively from 1 to 21. What you may well find in this session is a lot of resistance to scoring for fear it will be taken as a commitment that something is easy or can be delivered quickly. Reassure the team that this is not the case due to the relative scoring and even the work item that scored a 1 may still take half a year to deliver, it’s just that the rest will take even longer.

The other potential issue you may get from delivery teams is they start trying to come up with solutions there and then and keep asking details that don’t exist yet. Again, reassure them that these are rough estimates based on gut feel and what they already know of the project. Also be sure to reassure the team that they’re not being held to their estimates, this exercise is simply to identify the order the team is working on the work items.

Wrap up and Next actions

On closing this session it will be similar to the close of the first session. Thank your attendees and then explain what your next actions are going to be (tallying up the scores and sharing the prioritised list).

After both workshops

Once you have you completed your workshops you can proceed to calculate the Weighted Shortest Job First score.

Some tools like Jira may have the calculation built into the work items, entering your scores here and then using a Jira query to produce your list is an efficient way to work. If you don’t have an automated tool then you’ll need to create an Excel doc to perform your calculations. If you use Column A for work item Name, Column B for Business Value, Column C for Time Criticality, Column D for Risk Reduction/Opportunity Enablement, Column E for Job Size and Column F for Weighted Shortest Job First score then you can run a query on each row along the lines of =SUM((B2:D2)/E2). You will also want to round your scores (I prefer to go to 2 decimal places). Now add filters to you column headers and order the Weighted Shortest Job First score column to sort by Largest to Smallest, this will give you your top to bottom priority list.

Finally it’s time to share the list with all of your stakeholders. This may trigger further discussions if some items have turned out lower than expected, use this as an opportunity to reflect on either the scores the work item was given or the scope of the work item and hold a mini-workshop if something changes drastically to re-score the affected work item(s).

The other thing to keep in mind is that this is merely a technique to identify the priorities, ultimately the Product Manager and /or Product Owner get the final say on what the actual order is, you have presented them with a running order that gives the best ‘bang for your buck’.

There can also be reasons to adjust the list due to dependencies between work items i.e. there’s no point in adding an incredible postcode checker if you can’t yet add/view/edit the address field.

Technique Summary

Now you know what Weighted Shortest Job First is and why it is a great prioritisation technique. You also know that you will need to host a workshop or two to gather the scores from various stakeholders. You also know which stakeholders to invites and have an overview of how to run your workshops. Finally you also know how to complete the WSJF calculation and how to handle a work item being lower in the list that expected.

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