We’ve published quite a few articles about popular feature prioritization frameworks. We’ve done deep dives into Kano Models, RICE and more. But when it comes to prioritizing features in a manner that supports agile teams, it’s hard to do better than Weighted Shortest Job First, commonly referred to as WSJF. Keep reading to learn why Ascendle teams frequently turn to WSJF for feature prioritization.
The Definition of WSJF
Like all prioritization frameworks, WSJF aims to quantify the potential business value to be realized by the addition of a given feature. And similar to most models, WSJF also takes into account the estimated effort to produce said feature. However, WSJF goes one step further by introducing a new component to the equation: the Cost of Delay.
Cost of Delay
Simply put, Cost of Delay recognizes that if a given feature is intended to provide incremental value to a product, by definition, the lack of that feature will have a corresponding negative impact on the business. This impact is quantified as the Cost of Delay, which is made up of three components: user business value, time criticality and risk reduction:
1. User Business Value
This is the relative value to the business or customer. Each company that uses WSJF will measure this “value” differently and – like all frameworks – consistency is key. Are you anticipating increasing your user base or engagement within your tool? These are the questions that help us quantify user business value.
2. Time Criticality
Unlike most frameworks, WSJF acknowledges the critical role that time can play when predicting business value. In some situations, incremental improvements can be released without regard to the day or month. However, if your release must coincide with a major trade show or a customer request, the time criticality of a project can be substantial. In organizations where time criticality varies greatly, WSJF is often a superior framework.
3. Risk Reduction or Opportunity Enablement
The final component of the Cost of Delay quantifies Risk Reduction or Opportunity Enablement. If most of your competitors have a given feature, your organization’s release of a similar feature is a Risk Reduction; it hasn’t been added to increase business but to retain business. Likewise, features labeled as Opportunity Enablement indicate the ability to please new customers or existing customers in unique, new ways.
For each of the components of Cost of Delay, the recommended values to plug in would be derived from the Cohn Scale, a modified fibonacci sequence commonly used in agile to measure effort. Agile practitioners know that the purpose of the Cohn Scale isn’t to accurately measure anything. Rather, the goal is to be able to quantify one component relative to another one. Said differently, we’re not concerned if one feature is worth ten million dollars in revenue and the other is worth twenty million. Instead, we’re concerned that the user business value of one is two times that of the other.
The above three factors are then used to derive the formula for Cost of Delay.
The WSJF Formula
Once Cost of Delay has been calculated, dividing the result by the estimated effort to produce a given feature results in the WSJF score. Similar to the components of the Cost of Delay, Cohn Scale numbers are also recommended to estimate effort. Again, the concern isn’t to measure the number of hours or days required, only the amount of time required, relative to the other features that are being measured.
Benefits of Using Weighted Shortest Job First (WSJF) Model
Below are three benefits of using WSJF for prioritizing features or efforts:
1. WSJF Is More Comprehensive
Popular frameworks like Kano Models are fine for understanding the potential appeal of a given feature, and RICE acknowledges that effort needs to be juxtaposed with potential return. But WSJF stands alone for the introduction of time criticality. Indeed, depending on your industry or application, time criticality could be the most important component of all!
2. WSJF Quantifies the Unquantifiable
Software estimation is difficult. Ironically, so, too is quantifying both the potential appeal and time criticality of a given feature. But using numbers from the Cohn Scale ensures that the formula succeeds where it needs to; in assigning relativity to a list of features in a consistent manner.
3. WSJF is Agile Approved
To be clear, it takes a while for teams that haven’t worked in agile to get used to relative estimation. However, once they do, it becomes a valuable piece in their toolkit. For those teams that have worked in agile, WSJF fits like a glove, enabling them to properly prioritize their product backlogs.
Avoiding WSJF “Gotchas”
WSJF is a powerful feature prioritization framework. At the same time, here are few things to keep in mind as you attempt to role it into your organization:
- Your relative estimations are only as good as your relative estimating. Keep in mind that all four components of the WSJF formula rely on a proper understanding of how to apply relative point totals. As such, failures of your team to understand how to apply relative estimations will obviously create skewed results.
- Relative estimations can change over time. In particular, the user business value, time criticality and opportunity enablement components of the formula may shift as the market does. As such, it’s critical to revisit your formulas periodically to make sure they reflect the current state of business.
- WSJF can inhibit large features from being developed if teams don’t work to break them down into smaller components. In WSJF, the estimated effort is the denominator. Simply put, a large denominator will suppress scores from breaking through to the top of the backlog. Savvy ScrumMasters know this and work hard to find ways to chop features up into smaller components.
Teams with small feature lists or those that operate in verticals where competition isn’t a constant threat might consider WSJF to be overly complex for their needs. But for organizations that must consider multiple points of data and swiftly prioritize in a rigorous manner, WSJF serves as a valuable tool to maintain a competitive edge.