📘 Software Sizing (Software Project Management)

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🔹 1. Definition

Software sizing is the process of measuring the size of a software system to estimate effort, cost, time, and resources required for development.

👉 In simple words: It tells us how big the software is, so we can estimate how much work it needs.

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🔹 2. Purpose of Software Sizing

• Helps in project estimation
• Supports cost and effort prediction
• Improves planning and scheduling
• Helps compare different software projects
• Reduces project risk

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🔹 3. Importance ⭐

• Basis of software estimation models (like COCOMO)
• Used for resource allocation
• Helps in productivity measurement
• Essential for project planning

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🔹 4. Techniques of Software Sizing

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🔸 1. Lines of Code (LOC) 📏

Measures software size based on number of written code lines.

🔹 Formula:

Size = Total number of executable lines of code

💡 Example:

• Small program = 1000 LOC
• Large system = 50,000 LOC

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🔸 2. Function Point (FP) Analysis ⚙️

Measures size based on functionality delivered to the user.

🔹 Components:

• Inputs (EI)
• Outputs (EO)
• Queries (EQ)
• Internal Files (ILF)
• External Interfaces (EIF)

👉 Output = Function Points (FP)

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🔸 3. Object Points 🧩

Used in object-oriented systems.

Measures:

• Screens
• Reports
• Components

👉 Each is assigned a weight and total size is calculated.

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🔸 4. Use Case Points (UCP) 🎯

Based on use cases in system design.

Steps:

• Identify use cases
• Classify complexity
• Assign weights
• Calculate total points

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🔹 5. Software Sizing Process

📌 Step-by-step:

🔹 Step 1: Break system into components (WBS)

🔹 Step 2: Identify sizing method (LOC, FP, etc.)

🔹 Step 3: Measure each component

🔹 Step 4: Sum all values

🔹 Step 5: Convert size into effort/cost

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🔹 6. Diagram Description

📊 Software sizing flow:

Software System
   ↓
Decomposition (Modules)
   ↓
Size Measurement (LOC / FP / UCP)
   ↓
Total Size
   ↓
Effort & Cost Estimation

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🔹 7. Types of Software Sizing

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🔸 1. Absolute Sizing

• Based on actual measurable units (LOC, FP)

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🔸 2. Relative Sizing

• Based on comparison with similar systems

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🔹 8. Advantages of Software Sizing

✔ Helps in accurate estimation ✔ Supports planning and scheduling ✔ Improves project tracking ✔ Useful for cost prediction ✔ Helps compare project complexity

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🔹 9. Limitations ❌

• LOC depends on programming language
• Early estimation may be difficult
• Function points need expert judgment
• Can be subjective in complex systems

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🔹 10. Software Sizing vs Software Estimation

Feature	Software Sizing	Software Estimation
Meaning	Measures size	Predicts effort/time
Output	LOC / FP / UCP	Cost, time, effort
Stage	Early design	Planning phase
Dependency	Input for estimation	Uses sizing results

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🔹 11. Important Exam Points

• Software sizing = measuring software size
• Methods: LOC, FP, Object Points, Use Case Points
• Used as input for estimation models
• Essential for COCOMO and project planning

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🔹 12. Short Summary

• Software sizing measures how big a software system is
• Uses methods like LOC, Function Points, and Use Case Points
• It is the foundation for effort and cost estimation

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🔹 13. Quick Exam Answer (2–3 lines)

Software sizing is the process of measuring the size of a software system using methods like Lines of Code, Function Points, and Use Case Points. It helps in estimating effort, cost, and time required for software development.

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🔹 14. Likely Exam Questions

1. Define software sizing.
2. What are different software sizing techniques?
3. Explain LOC method.
4. What is Function Point Analysis?
5. Why is software sizing important?
6. Differentiate between software sizing and estimation.
7. Draw software sizing process diagram.