Weighted Shortest Job First (WSJF) is a popular prioritization method employed across various industries, finding utility within Agile and the Scaled Agile Framework (SAFe). Organizations use this technique to objectively sequence large bodies of work, such as features or epics, based on economic principles. This article provides a practical, step-by-step guide detailing the calculation of this metric for effective job prioritization.
What is Weighted Shortest Job First (WSJF)?
WSJF is a sequencing model designed to maximize the economic benefit derived from a stream of work. It is rooted in Lean economics and adapts the Shortest Job First rule from queuing theory. The method determines the optimal order for delivering features or capabilities to ensure the highest throughput of value. This systematic approach moves prioritization away from subjective opinions.
The Economic Imperative: Cost of Delay
The foundational premise of WSJF is the Cost of Delay (CoD), which represents the financial impact of delaying a specific job. This economic principle drives the calculation, shifting focus from the cost of implementation to the cost of not implementing promptly. CoD forms the numerator of the WSJF formula: WSJF equals the Cost of Delay divided by the Job Size.
Deconstructing the Cost of Delay (CoD)
Cost of Delay is a composite score derived from the sum of three independent variables. To maintain simplicity and facilitate team consensus, these variables are estimated using relative sizing, often utilizing a modified Fibonacci sequence, instead of calculating absolute monetary figures. The goal is to score each variable relative to a baseline item.
User-Business Value
User-Business Value quantifies the relative worth a job delivers to the customer or the wider organization. This score captures factors such as potential for new revenue generation or the avoidance of future financial penalties. It also accounts for the strategic importance of the work in advancing the organization’s long-term goals. For example, a feature that unlocks a new market segment would receive a significantly higher score.
Time Criticality
Time Criticality assesses how quickly the value of a job diminishes over time. Jobs with strict regulatory deadlines or those tied to specific competitive market windows score highly in this component. Seasonal dependencies, where value is only available for a short period, also increase this score. If delaying a job means missing a market opportunity, the urgency reflected will be elevated.
Risk Reduction and Opportunity Enablement
This component captures the value derived from jobs that do not directly deliver immediate user features but are important for future progress. Risk reduction includes work like cleaning up technical debt or enhancing system security to prevent failures. Opportunity enablement refers to foundational work, such as building a reusable API platform, that unlocks the potential for many future features. The value is measured by the extent to which the work reduces future uncertainty or accelerates future value delivery.
Estimating Job Size (The Denominator)
Job Size represents the denominator in the WSJF formula and quantifies the relative effort or duration required to complete the work. The execution teams responsible for delivery must provide this estimate to reflect the practical realities of implementation complexity. The size estimate must use the same relative sizing scale employed for the Cost of Delay components. Favoring the “shortest job first” means the model seeks a small denominator, thereby elevating smaller jobs that deliver value rapidly.
Practical Guide to Calculating WSJF Scores
Establishing the Baseline and Relative Scoring
The calculation process begins by establishing a shared understanding of the relative sizing scale, such as the sequence 1, 2, 3, 5, 8, 13, 20. Next, select a baseline job that is small, well-defined, and understood by the estimation group. This baseline item is assigned an anchor score (e.g., 5) for all four variables: the three Cost of Delay components and Job Size. All other jobs are then scored relative to this established baseline for each of the four variables individually. This relative scoring process continues until all jobs have scores for the three Cost of Delay components and the Job Size.
Calculate Cost of Delay (CoD)
The next step aggregates the scores to calculate the Cost of Delay, which forms the numerator of the WSJF formula. This is achieved by summing the three relative scores: User-Business Value, Time Criticality, and Risk Reduction/Opportunity Enablement. For instance, a job with individual scores of 8, 5, and 3 would have a total CoD score of 16.
Determine the WSJF Score
The final WSJF calculation is performed by dividing the calculated Cost of Delay score by the Job Size score. If the job’s implementation size was estimated at 8, the WSJF score would be 16 divided by 8, resulting in a score of 2.0.
Sequence the Work
The final step is interpreting the resulting WSJF scores to determine the sequence of work. A high Cost of Delay combined with a low Job Size (e.g., CoD 20 / Size 2) yields a high WSJF score of 10.0, indicating a high-priority item. This structure ensures that jobs delivering high value quickly are sequenced ahead of those requiring significantly more effort or delivering less value.
Using WSJF Scores for Portfolio Prioritization
Once WSJF scores have been calculated for all potential jobs, the organization uses them to sequence the portfolio of work. Jobs are sequenced strictly in descending order based on their score, meaning the job with the highest score is undertaken next. This objective sequencing provides stakeholders with clear, economically transparent reasoning for the order of delivery. Since market conditions and technical estimates are dynamic, WSJF scores are not permanent values. The scores should be revisited and recalculated periodically, especially when new information becomes available, ensuring continuous prioritization.