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PMP lesson · Delivery Approach · Agile foundations · lesson 3 of 4 · about 6 minutes

Iterations, increments and timeboxing

Agile and hybridFree preview
Goal: After this lesson you can explain iterative vs incremental delivery, why timeboxes are fixed, and the basic rhythm of a sprint.

1The situation

“Just one more week”

The MES team's two-week sprint is ending, and a feature is almost done. A developer suggests: “Let's extend the sprint by three days and finish it.”

It sounds reasonable. But next time it will be four days, then a week. Soon there is no rhythm, no predictable review date, and no honest picture of how much the team really finishes in two weeks.

Timeboxes are fixed for a reason.

2Iterative vs incremental

Agile combines two ideas:

Iterative
Improve
Repeat cycles to refine the solution through feedback.
HMI mock-up → prototype → final
Incremental
Add
Deliver usable pieces that build on each other.
Cell 1, then cell 2…
Timebox
Fixed length
A fixed maximum time; scope flexes, the box doesn't.
2-week sprint
When time runs out, scope moves, not the timebox: unfinished items go back to the backlog.

3Incremental vs iterative

Incremental: one finished piece at a time Cell 1 complete → cells 1–2 complete → … Iterative: the whole thing, improved each cycle sketchbetterfinal HMI: paper mock-up → clickable prototype → final screens
Agile does both: usable pieces, improved through feedback.

4How it looks on the exam

Exam-style question 1. At the end of a sprint, a story is about 80 percent complete. A developer proposes extending the sprint by three days. What should the team do?
A. Extend the sprint
B. End the sprint on time and return the unfinished story to the product backlog
C. Count 80 percent of the story's points
D. Split the story and claim the finished part as done without meeting the definition of done
Show the answer and the decode
Answer: B.
In simple English
Unfinished work at the end of a timebox.
What is the question really asking?
The right handling.
Key words / trigger
“extending the sprint”
PMP logic
Timeboxes are fixed; unfinished work returns to the backlog.
Why the wrong answer looks attractive
Extending feels practical, but it breaks the rhythm and hides real capacity.

5Remember this

Your memory card

  • Iterative = improve · incremental = add usable pieces · agile = both
  • Timebox: fixed duration; scope flexes
  • Unfinished at the end → back to the backlog; no sprint extensions
  • Sprint rhythm: planning → daily → review → retrospective
The full lesson in the PMCLEAR app also has:
  • the rest of the lesson (Why fixed timeboxes)
  • a worked example
  • the common traps (wrong vs right)
  • 2 exam-style questions with the decode
  • a 3-question quick check
Open the full lesson → Create a free account
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