Understanding Service Level Expectations (SLE) and Cycle Time in Scrum with Kanban
Service Level Expectations (SLE) are set to help Scrum Teams predict the likelihood of completing work within a specific timeframe. When a work item ages past a certain percentile of your dataset, it may affect the confidence in meeting the SLE.
Exam Question
Your Scrum Team’s cycle time is currently 8 days or less with 85% confidence. The team has set the Service Level Expectations (SLE) accordingly. If an item in progress has just aged past your dataset’s 50th percentile, what can we say about the chance it will fail to meet the team’s 8-day SLE?
(choose the best answer)
A. There is now a higher chance to meet the team’s SLE.
B. There is now a lower chance it will meet the team’s SLE.
C. We cannot predict with any level of confidence what will happen with the work item at this point.
D. Nothing changed. We’re still 85% confident the card will meet the SLE.
Correct Answer
D. Nothing changed. We’re still 85% confident the card will meet the SLE.
Explanation
Correct Answer
D. Nothing changed. We’re still 85% confident the card will meet the SLE:
The Service Level Expectation (SLE) is based on historical data, indicating that 85% of the work items are completed in 8 days or less. When a work item ages past the 50th percentile, it still falls within the confidence interval defined by the SLE. The 50th percentile represents the median cycle time, meaning that while the item is taking longer than some others, it is still within the range where 85% of items are completed within the 8-day window. Therefore, the initial confidence level of 85% still holds, and there is no immediate indication that the SLE will not be met.
Why the Other Options Are Less Appropriate
A. There is now a higher chance to meet the team’s SLE:
This is incorrect because passing the 50th percentile does not increase the likelihood of meeting the SLE. The SLE is based on an 85% confidence level, and the item is still within that range.
B. There is now a lower chance it will meet the team’s SLE:
This is incorrect because even though the item has aged past the 50th percentile, it is still within the range where 85% of items are expected to be completed on time. The confidence level remains unchanged.
C. We cannot predict with any level of confidence what will happen with the work item at this point:
This is incorrect because the SLE provides a clear prediction based on historical data, and the 85% confidence level still applies.
Relevance to the PSK I Exam
Understanding how SLEs work and how to interpret them in real-time scenarios is crucial for the PSK I exam. It demonstrates the ability to manage and predict workflow effectively within the Scrum with Kanban framework.
Key Takeaways
- SLEs provide a confidence level based on historical data, and passing the 50th percentile does not change the initial prediction.
- The confidence level of 85% remains valid as long as the work item is within the expected cycle time range.
- Understanding SLEs helps teams manage work predictably and maintain confidence in their workflow predictions.
Conclusion
When a work item ages past the 50th percentile, it does not change the 85% confidence level that the item will meet the SLE. This understanding helps teams maintain confidence in their workflow predictions and manage work effectively. For more information on preparing for the PSK I exam, visit our Professional Kanban PSK I™ Exam Prep.
