Measuring the interest
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
express debt in concrete costs.
Planned topics
- Costs are time, risk, and money: slower changes, incident frequency, onboarding time, infrastructure cost.
- Gather evidence: how long a typical change in this area takes, how many incidents trace to it, how often it is touched (from version history).
- Estimate interest per month, such as engineer-days lost, plus the probability and cost of failure.
- Admit uncertainty with ranges rather than false precision.
Draft outline details
Demonstration
Worked estimate: order pricing module touched 18 times last quarter; each change takes about 2 extra days due to missing tests; interest about 36 engineer-days per quarter, plus 2 incidents.
Check your understanding
What three kinds of cost express interest?
Show answer
Time, risk, and money.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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