- 2068 Chaitra · 2.5 marks
Short note: COCOMO
Short answer
COCOMO by Barry Boehm is an algorithmic cost model: Effort E = a × (KLOC)^b PM, time D = c × E^d months. Modes: organic (a=2.4, b=1.05), semi-detached (3.0,1.12), embedded (3.6,1.20) with c=2.5, d=0.38/0.35/0.32. Levels: basic, intermediate (15 cost drivers), detailed. COCOMO II adds scale factors and function points.
Write a short note on COCOMO.
COCOMO (Constructive Cost Model) is an algorithmic model by Barry Boehm (1981) that estimates software effort and schedule from the estimated size in KLOC.
Basic equations
- Effort E = a × (KLOC)^b person-months
- Development time D = c × (E)^d months
- Staff = E / D; Productivity = KLOC / E
Modes
| Mode | Project type | a | b | c | d |
|---|---|---|---|---|---|
| Organic | Small, familiar, simple | 2.4 | 1.05 | 2.5 | 0.38 |
| Semi-detached | Medium, mixed experience | 3.0 | 1.12 | 2.5 | 0.35 |
| Embedded | Tight constraints | 3.6 | 1.20 | 2.5 | 0.32 |
Levels: basic (size only), intermediate (15 cost drivers form an effort adjustment factor) and detailed (cost drivers per phase).
Example: a 32 KLOC organic project needs E = 2.4 × 32^1.05 ≈ 91 PM and D = 2.5 × 91^0.38 ≈ 13.9 months.
COCOMO II updates the model with scale factors, effort multipliers and size measures such as object points and function points. COCOMO is simple and well documented, but its accuracy depends on a good size estimate and on calibration to the organisation's own data.
✓ Answer checked by Claude Opus 5.5 (high effort)