Week 4 · Quick revision and self-check
On this page 8 headings
Key definitions
| Topic | Lecture summary |
|---|---|
| PM responsibilities | Main point of contact between clients and dev team; Form and manage the dev team; Project scheduling; Project estimation; Risk management; Configuration management |
| Estimation importance | Cost, schedule, bidding |
| Empirical vs heuristic | Experience-based judgement versus mathematical relationships |
| Expert-judgement drawbacks | Human errors and individual bias; optimistic estimates; overlooked factors or inadequate knowledge; senior/assertive group members may dominate. |
| KLOC | 1,000 lines of code |
| Person-month | One person’s work in one month; 12 PM = 12 × 1 = 4 × 3 = 2 × 6 |
| Delphi | Independent estimates with anonymous summaries, repeated rounds and no discussion between experts |
| COCOMO types | Organic: well-understood, small experienced team; Semi-detached: mixed experience with limited related-system experience; Embedded: strongly coupled with hardware, possibly large inexperienced team |
| Cost drivers (EAF) | 15 drivers: product, computer, personnel and project attributes; multiply their factors. Four selected factors: 1.40, 1.08, 1.13, 0.95. |
| Scheduling activities | Identify major activities; Break activities into tasks; Determine dependencies; Estimate each task’s duration; Represent tasks in a diagram; Assign start and end dates; Find the critical path; Allocate resources |
| WBS | Root = project; break nodes into children; leaves = tasks allocated to developers, roughly two weeks |
| Activity network | WBS leaves become nodes; dependencies and durations |
| Critical path | A chain of tasks that determines the duration of the project. |
| Risk categories and assessment | Technical / project / business. Ask for the worst-case scenario; P from 0–100%; impact 1–4; Risk = P × I; sort descending. |
| Scrum roles | Development Team: required skills; Product Owner: client/team interface and value; Scrum Master: supports Scrum activities, team and organisation |
| Product backlog | Prioritized work; sprint work chosen collectively in sprint planning |
| Daily scrum | What did I work on yesterday? What am I working on today? What issues are blocking me? |
| Velocity | Points completed per sprint; 2 + 2 → velocity = 4 |
| Icebox | Future ideas not prioritized yet, e.g. Customer feedback and Order tracking |
Five practice questions with answers
1. A system needs 5,000 LOC. What is its size?
Answer: 5 KLOC. This estimates size, not person-month effort.
2. An illustration shows 4 developers working for 3 months. What is the nominal effort?
Answer: 4 × 3 = 12 person-months, assuming comparable full-time effort.
3. A risk has P=40% and impact=3. What is its risk score?
Answer: 0.40 × 3 = 1.2; it is neither 120% nor ₹1.2.
4. A sprint completes stories worth 2, 1 and 3 points. What is observed velocity?
Answer: 2 + 1 + 3 = 6 points for that sprint.
5. In Delphi, after anonymous summary feedback, which stage repeats?
Answer: The experts independently submit revised estimates; the final estimate does not trigger the loop.
COCOMO slide values and corrected calculation
| Step | Slide value | Correct calculation |
|---|---|---|
| Initial effort = 3.0 × 4^1.12 | 15.83 PM | ≈ 14.17 PM |
| Effort adjustment factor = 1.40 × 1.08 × 1.13 × 0.95 | 1.62 | 1.62 |
| Final estimate = initial × EAF | 25.65 PM | ≈ 23.0 PM |
| Cost before adjustment (rounded initial effort), at ₹75,000 per person per month | 16 × 75,000 = ₹12 lakh | 14 × 75,000 ≈ ₹10.5 lakh |
Using the adjusted effort of approximately 23.0 person-months, the adjusted cost is 23.0 × ₹75,000 ≈ ₹17.25 lakh. The initial cost before adjustment is approximately ₹10.63 lakh without rounding effort to 14 PM.
The slide's 15.83 PM does not follow from 3.0 × 4^1.12 (which evaluates to ≈14.17). The method is unchanged; only the arithmetic differs. If asked to compute, use the correct value; if asked what the lecture states, it is 15.83 PM.