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COCOMO for 49,200 lines of code
Short answer
COCOMO (Constructive Cost Model) estimates effort and schedule from KLOC. For 49,200 LOC (49.2 KLOC) in organic mode: Effort = 2.4 × 49.2^1.05 ≈ 143.5 person-months; Development time = 2.5 × 143.5^0.38 ≈ 16.5 months; Average staffing = 143.5/16.5 ≈ 9 persons; Productivity = 49200/143.5 ≈ 343 LOC/person-month.
What is COCOMO? Calculate COCOMO effort, development time in month, average staffing and productivity that is estimated to be 49,200 lines of code.
What is COCOMO
COCOMO (Constructive Cost Model) is an algorithmic cost estimation model developed by Barry Boehm (1981). It estimates the effort (person-months) and development time (months) of a software project from its size in thousands of delivered lines of code (KLOC).
Three modes (project classes):
| Mode | Description | a | b | c | d |
|---|---|---|---|---|---|
| Organic | Small team, familiar problem, flexible requirements (about 2–50 KLOC) | 2.4 | 1.05 | 2.5 | 0.38 |
| Semi-detached | Medium size, mixed experience (about 50–300 KLOC) | 3.0 | 1.12 | 2.5 | 0.35 |
| Embedded | Tight hardware/software/operational constraints | 3.6 | 1.20 | 2.5 | 0.32 |
Three levels: basic (effort from size only), intermediate (size plus 15 cost drivers giving an effort adjustment factor) and detailed (cost drivers applied to each phase). COCOMO II (1995/2000) updated the model for modern development.
Basic COCOMO equations:
- Effort E = a × (KLOC)^b person-months
- Development time D = c × (E)^d months
- Average staffing = E / D persons
- Productivity = KLOC / E
Calculation for 49,200 lines of code
Size = 49,200 LOC = 49.2 KLOC.
Mode chosen: organic. 49.2 KLOC lies within the usual organic range (up to about 50 KLOC), and no tight constraints, new technology or inexperienced team are mentioned. So a = 2.4, b = 1.05, c = 2.5, d = 0.38.
1. Effort E = 2.4 × (49.2)^1.05 (49.2)^1.05 = 59.78 E = 2.4 × 59.78 = 143.5 person-months
2. Development time D = 2.5 × (143.47)^0.38 (143.47)^0.38 = 6.600 D = 2.5 × 6.600 = 16.5 months
3. Average staffing S = E / D = 143.47 / 16.50 = 8.69 ≈ 9 persons
4. Productivity P = Size / E = 49,200 / 143.47 = 342.9 LOC per person-month (≈ 0.343 KLOC/PM)
| Quantity | Result |
|---|---|
| Effort | 143.5 PM |
| Development time | 16.5 months |
| Average staffing | ≈ 9 persons |
| Productivity | ≈ 343 LOC/PM |
Note: if the project were treated as semi-detached (since 49.2 KLOC is close to 50 KLOC), the result would be E = 3.0 × 49.2^1.12 = 235.6 PM, D = 16.9 months, about 14 persons and 209 LOC/PM.
✓ Answer checked by Claude Opus 5.5 (high effort)
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