What is Weighted Shortest Job First (WSJF)? WSJF explanation, importance, and FAQs.

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Weighted Shortest Job First 

Weighted shortest job first or WSJF is a tool for prioritisation of a task. 

It’s a calculation to determine whether it is profitable to work on a specific task over another task at a given time. So what determines the situation that we are talking about? 

The situation can be the urgency of performing a task.

It can be any specific challenge, which might force a team to rethink whether to proceed with a given task or to delay it for a while and focus on some other task which might yield better results at the moment.

WSJF is a mathematical calculation of risk involved in dropping a task for later or picking up a task for the current situation over any other task by comparing cost of delay with job duration.

WSJF calculation

The calculation of WSJF involves-

Cost of Delay (CoD): A relative score, calculated by the score of three factors

  • User/business value: how valuable a job is for the customer. Like the one with greater revenue generation or higher customer appeal will be rated high.
  • Time criticality: Is there any significant change occurring in the user/business value over a particular period of time that may alter our market? Or competitiveness.
  • Risk reduction/opportunity enablement value: This involves future consequences associated with each job.

CoD is calculated by adding above scores.

Job duration or job size: It is a relative measure of time involved in the tasks that are being compared. We aren’t using a direct value of time because that would mess up the calculations. The team assigns a score to each task as per their assessment. Job size is the estimated amount of work that has to be done to complete a task.

Now we know about these two terms that are going to create the formula for our weighted shortest job first calculation. It is the ratio of the cost of delay to job duration.

WSJF= CoD / Job duration ;

A few things that can be noted from this: The cost of delay is directly proportional to the WSJF score, meaning that a task with a higher cost of delay shall be prioritized higher. 

Similarly the job duration has an inversely proportional relation with WSJF. 

That means if a task consumes way less time then it shall be prioritised high as it is easy to complete and shed the workload.

So a balance between these two provides us with a clearer picture of prioritisation.

Implementing WSJF results

This method can be applied by any team or team member to weigh the importance of each task that lay ahead and to set priorities likewise after studying the results.

It helps to find a solution whenever there is conflict between multiple projects on the roadmap that you are required to work on.

For example, the development team can use the figures to determine whether a particular feature which they want to add shall be added as soon as possible or if they can wait for it and work on a different feature which the competitors might also be planning to launch soon.

FAQs

Q: What principle does WSJF follow?

A: The basic principle is evaluating a score for the tasks by measuring them on parameters of cost of delay and job duration or size.

Q: What is weighted shortest job?

A: After the application of WSJF calculations, the end result obtained tells us which job is to be prioritized highest is the weighted shortest job.
From the term itself, this is the job that weighs more and takes up less time than most of the other jobs on the list.

Q: Who can use WSJF?

A: Any individual employee or any team can use this method to prioritize their work efficiently.

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