Intermediate COCOMO Cost Drivers and Multipliers
In Intermediate COCOMO, the Effort Adjustment Factor (EAF) is calculated based on 15 cost drivers. Each driver has a rating that corresponds to a multiplier. These cost drivers are categorized into four groups.
1. Product Attributes
| Cost Driver | Very Low | Low | Nominal | High | Very High | Extra High |
|---|---|---|---|---|---|---|
| Required Software Reliability (RELY) | 0.75 | 0.88 | 1.00 | 1.15 | 1.40 | - |
| Database Size (DATA) | - | 0.94 | 1.00 | 1.08 | 1.16 | - |
| Product Complexity (CPLX) | 0.70 | 0.85 | 1.00 | 1.15 | 1.30 | 1.65 |
2. Hardware Attributes
| Cost Driver | Very Low | Low | Nominal | High | Very High | Extra High |
|---|---|---|---|---|---|---|
| Execution Time Constraint (TIME) | - | - | 1.00 | 1.11 | 1.30 | 1.66 |
| Main Storage Constraint (STOR) | - | - | 1.00 | 1.06 | 1.21 | 1.56 |
| Virtual Machine Volatility (VIRT) | 0.87 | 0.94 | 1.00 | 1.10 | 1.15 | - |
| Turnaround Time (TURN) | - | 0.87 | 1.00 | 1.07 | 1.15 | - |
3. Personnel Attributes
| Cost Driver | Very Low | Low | Nominal | High | Very High | Extra High |
|---|---|---|---|---|---|---|
| Analyst Capability (ACAP) | 1.46 | 1.19 | 1.00 | 0.86 | 0.71 | - |
| Programmer Capability (PCAP) | 1.42 | 1.17 | 1.00 | 0.86 | 0.70 | - |
| Application Experience (AEXP) | 1.29 | 1.13 | 1.00 | 0.91 | 0.82 | - |
| Platform Experience (PEXP) | 1.19 | 1.09 | 1.00 | 0.91 | 0.85 | - |
| Language and Tool Experience (LTEX) | 1.20 | 1.09 | 1.00 | 0.91 | 0.84 | - |
4. Project Attributes
| Cost Driver | Very Low | Low | Nominal | High | Very High | Extra High |
|---|---|---|---|---|---|---|
| Use of Modern Software Practices (MODP) | 1.24 | 1.10 | 1.00 | 0.91 | 0.82 | - |
| Use of Software Tools (TOOL) | 1.24 | 1.10 | 1.00 | 0.91 | 0.83 | - |
| Required Development Schedule (SCED) | 1.23 | 1.08 | 1.00 | 1.04 | 1.10 | - |
Example of Calculating EAF:
For example, assume the following ratings for the cost drivers:
- Required Software Reliability (RELY) = 1.15 (High)
- Database Size (DATA) = 1.00 (Nominal)
- Product Complexity (CPLX) = 1.15 (High)
- Programmer Capability (PCAP) = 0.86 (High)
- Use of Software Tools (TOOL) = 0.91 (High)
The EAF is calculated by multiplying the values of these drivers:
\[ \text{EAF} = 1.15 \cdot 1.00 \cdot 1.15 \cdot 0.86 \cdot 0.91 \approx 1.01 \]
Questions
You are tasked with estimating the effort for a small Organic software project with an estimated size of 10 KLOC (thousand lines of code).
Cost Drivers:
- Required Software Reliability (RELY): 1.15 (High)
- Programmer Capability (PCAP): 0.86 (High)
- Use of Software Tools (TOOL): 0.91 (High)
The Effort Adjustment Factor (EAF) is calculated as:
\[\text{EAF} = 1.15 \cdot 0.86 \cdot 0.91 \approx 0.90\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Organic projects:
- a = 2.4
- b = 1.05
Tasks:
Calculate the effort (in person-months).
Calculate the effort (in person-months).
Effort (in person-months):
\[\text{Effort} = 2.4 \cdot (10)^{1.05} \cdot 0.90 \approx 22.8 \text{ person-months}\]
Estimate the development time (in months).
Estimate the development time (in months).
Development Time:
\[\text{Development Time} = 2.5 \cdot (22.8)^{0.38} \approx 10.4 \text{ months}\]
A medium-sized Semi-Detached project is estimated to have 50 KLOC.
Cost Drivers:
- Product Complexity (CPLX): 1.30 (Very High)
- Analyst Capability (ACAP): 0.86 (High)
- Required Development Schedule (SCED): 1.10 (Very High)
The EAF is calculated as:
\[\text{EAF} = 1.30 \cdot 0.86 \cdot 1.10 \approx 1.23\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Semi-Detached projects:
- a = 3.0
- b = 1.12
Tasks:
Calculate the effort (in person-months).
Calculate the effort (in person-months).
Effort (in person-months):
\[\text{Effort} = 3.0 \cdot (50)^{1.12} \cdot 1.23 \approx 207.3 \text{ person-months}\]
Estimate the development time (in months).
Estimate the development time (in months).
Development Time:
\[\text{Development Time} = 2.5 \cdot (207.3)^{0.35} \approx 18.9 \text{ months}\]
A large Embedded project is estimated at 200 KLOC.
Cost Drivers:
- Platform Volatility (PVOL): 1.15 (Very High)
- Programmer Capability (PCAP): 0.88 (High)
- Application Experience (AEXP): 0.91 (High)
The EAF is calculated as:
\[\text{EAF} = 1.15 \cdot 0.88 \cdot 0.91 \approx 0.92\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Embedded projects:
- a = 3.6
- b = 1.20
Tasks:
Calculate the effort (in person-months).
Calculate the effort (in person-months).
Effort (in person-months):
\[\text{Effort} = 3.6 \cdot (200)^{1.20} \cdot 0.92 \approx 1412.1 \text{ person-months}\]
Estimate the development time (in months).
Estimate the development time (in months).
Development Time:
\[\text{Development Time} = 2.5 \cdot (1412.1)^{0.32} \approx 32.3 \text{ months}\]
A tiny Organic project is estimated at 2 KLOC.
Cost Drivers:
- Required Software Reliability (RELY): 1.10 (High)
- Use of Modern Software Tools (TOOL): 0.91 (High)
- Team Cohesion (TEAM): 0.92 (High)
The EAF is calculated as:
\[\text{EAF} = 1.10 \cdot 0.91 \cdot 0.92 \approx 0.92\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Organic projects:
- a = 2.4
- b = 1.05
Tasks:
Calculate the effort (in person-months).
Calculate the effort (in person-months).
Effort (in person-months):
\[\text{Effort} = 2.4 \cdot (2)^{1.05} \cdot 0.92 \approx 4.8 \text{ person-months}\]
Estimate the development time (in months).
Estimate the development time (in months).
Development Time:
\[\text{Development Time} = 2.5 \cdot (4.8)^{0.38} \approx 6.3 \text{ months}\]
A Semi-Detached project has an estimated size of 30 KLOC.
Cost Drivers:
- Required Development Schedule (SCED): 1.04 (High)
- Analyst Capability (ACAP): 0.86 (High)
- Language and Tool Experience (LTEX): 0.91 (High)
The EAF is calculated as:
\[\text{EAF} = 1.04 \cdot 0.86 \cdot 0.91 \approx 0.81\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Semi-Detached projects:
- a = 3.0
- b = 1.12
Tasks:
Calculate the effort (in person-months).
Calculate the effort (in person-months).
Effort (in person-months):
\[\text{Effort} = 3.0 \cdot (30)^{1.12} \cdot 0.81 \approx 79.6 \text{ person-months}\]
Estimate the development time (in months).
Estimate the development time (in months).
Development Time:
\[\text{Development Time} = 2.5 \cdot (79.6)^{0.35} \approx 13.7 \text{ months}\]
An Embedded project has an estimated size of 150 KLOC.
Cost Drivers:
- Required Software Reliability (RELY): 1.15 (High)
- Product Complexity (CPLX): 1.30 (Very High)
- Programmer Capability (PCAP): 0.86 (High)
The EAF is calculated as:
\[\text{EAF} = 1.15 \cdot 1.30 \cdot 0.86 \approx 1.28\]
\( \text{Effort (person-months)} = a \cdot (KLOC)^b \cdot EAF \)
Constants for Embedded projects:
- a = 3.6
- b = 1.20
Tasks: