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# SOFTWARE COST ESTIMATION

I. CÁC PHƯƠNG PHÁP LUẬN CƠ BẢN

Algorithmic Models (Mô hình thuật toán)

COCOMO (Constructive Cost Model)
- Basic COCOMO
- Intermediate COCOMO
- Detailed COCOMO
- COCOMO II (phiên bản hiện đại)
Function Point Analysis (FPA)
Use Case Points (UCP)
SLIM Model
Putnam Model

Expert Judgment (Đánh giá chuyên gia)

Delphi Technique
Work Breakdown Structure (WBS)
Planning Poker (Agile)

Analogy-Based Estimation

So sánh với dự án tương tự
Case-Based Reasoning

Parametric Models

Dựa trên các tham số lịch sử
Phân tích hồi quy

II. CÁC PHƯƠNG PHÁP THỰC TẾ ĐANG ÁP DỤNG

Agile Estimation

Story Points

- Fibonacci sequence: 1, 2, 3, 5, 8, 13, 21...
- T-shirt sizing: XS, S, M, L, XL
- Relative estimation

Planning Poker

Team-based estimation
Consensus building
Velocity tracking

Bucket System

Nhanh hơn Planning Poker
Phù hợp với backlog lớn

Three-Point Estimation

Công thức PERT:
Expected Time = (Optimistic + 4×Most Likely + Pessimistic) / 6

Ví dụ:
- Optimistic: 10 ngày
- Most Likely: 15 ngày  
- Pessimistic: 26 ngày
Expected = (10 + 4×15 + 26) / 6 = 16 ngày

Bottom-Up Estimation

Ước lượng từng task nhỏ
Tổng hợp lên cao
Chi tiết và chính xác

Top-Down Estimation

Bắt đầu từ tổng quan
Phân rã xuống chi tiết
Nhanh nhưng ít chính xác hơn

T-Shirt Sizing

XS: < 1 ngày
S:  1-3 ngày
M:  3-5 ngày
L:  5-10 ngày
XL: > 10 ngày

III. CÔNG CỤ/PHẦN MỀM ƯỚC LƯỢNG

Project Management Tools

Jira Software

Story points estimation
Velocity charts
Burndown/Burnup charts
Sprint planning tools

Azure DevOps

Capacity planning
Velocity tracking
Work item estimation

Microsoft Project

Gantt charts
Resource allocation
Critical path analysis

Estimation-Specific Tools

COCOMO Calculator

Constructive Cost Model
Effort/Duration estimation
Team size calculation

Function Point Workbench

Function Point Analysis
Automated counting

Estimate Professional

Multiple estimation methods
Risk analysis

Agile Planning Tools

Planning Poker Online

PlanningPoker.com
Scrum Poker Online
Pointing Poker

Miro/Mural

Virtual estimation sessions
Collaborative planning

Spreadsheet Templates

Excel/Google Sheets

Ví dụ template:
┌─────────────┬──────────┬──────────┬──────────┬──────────┐
│ Task        │ Best Case│ Expected │ Worst    │ PERT Est │
├─────────────┼──────────┼──────────┼──────────┼──────────┤
│ Design DB   │ 3 days   │ 5 days   │ 8 days   │ 5.2 days │
│ API Dev     │ 5 days   │ 8 days   │ 15 days  │ 8.7 days │
│ Testing     │ 2 days   │ 4 days   │ 7 days   │ 4.2 days │
└─────────────┴──────────┴──────────┴──────────┴──────────┘

AI-Powered Tools

Software Analytics Platforms

Linear B
Code Climate Velocity
Waydev

Machine Learning Models

Dựa trên dữ liệu lịch sử
Predictive analytics

IV. PHƯƠNG PHÁP ƯỚC LƯỢNG THEO QUY MÔ

Startup/Small Projects

Story Points + Planning Poker
T-shirt sizing
Expert judgment

Medium Projects

Function Points
Use Case Points
Three-point estimation
Jira/Azure DevOps

Large Enterprise Projects

COCOMO II
Parametric models
Hybrid approaches
MS Project + custom tools

V. BEST PRACTICES

Kết hợp nhiều phương pháp

Ví dụ:
1. Expert judgment (ban đầu)
2. Planning Poker (chi tiết)
3. Three-point estimation (rủi ro)
4. Historical data (hiệu chỉnh)

Continuous Refinement

Re-estimate định kỳ
Track actual vs estimated
Improve accuracy theo thời gian

Buffer Management

Contingency Reserve: 10-20% cho rủi ro đã biết
Management Reserve: 5-10% cho rủi ro không biết

Documentation

Ghi lại assumptions
Track estimation accuracy
Lessons learned

VI. XU HƯỚNG HIỆN NAY

Data-Driven Estimation

Sử dụng dữ liệu lịch sử
Machine learning predictions

Continuous Estimation

Real-time adjustments
Automated tracking

Evidence-Based Scheduling

Monte Carlo simulations
Probabilistic forecasting

DevOps Metrics

Lead time
Cycle time
Deployment frequency

Khuyến nghị thực tế:

Agile teams: Story Points + Planning Poker + Jira
Traditional PM: WBS + Three-point + MS Project
Hybrid: Kết hợp COCOMO II + Agile estimation
Startups: T-shirt sizing + Excel templates

Bài toán thực tế:

Yêu cầu từ phía khách hàng và tất cả yêu cầu đang là high level, một số buổi thảo luận và làm rõ yêu cầu nhưng không nhiều thời gian để có thể phân tích chi tiết. KH yêu cầu gửi một báo giá cho khách hàng về nhân sự, thời gian dựa trên yêu cầu high level của khách hàng.

B # PHƯƠNG PHÁP ƯỚC LƯỢNG CHO YÊU CẦU HIGH-LEVEL

I. PHƯƠNG PHÁP ĐỀ XUẤT

Recommended Approach: HYBRID METHOD

┌─────────────────────────────────────────────────────┐
│  ANALOGOUS + EPIC-LEVEL + THREE-POINT + BUFFER      │
└─────────────────────────────────────────────────────┘

II. QUY TRÌNH ƯỚC LƯỢNG 5 BƯỚC

BƯỚC 1: Epic-Level Breakdown (2-4 giờ)

High-Level Requirements
    ↓
Epic Level Features
    ↓
Major Components

Template phân tích:

PROJECT: [Tên dự án] DURATION: [Estimate] months

EPIC BREAKDOWN

USER MANAGEMENT
- Authentication & Authorization
- User Profile Management

- Role & Permission
CORE FUNCTIONALITY

[Feature A]
[Feature B]
[Feature C]
3. INTEGRATION
Third-party APIs
Payment Gateway
Email/SMS Service

ADMIN PANEL

Dashboard & Reports
Configuration

INFRASTRUCTURE

Database Design
DevOps Setup
Security Implementation

BƯỚC 2: T-Shirt Sizing với Reference (1-2 giờ)

Sử dụng dự án tương tự làm benchmark:

SIZE DEFINITION (Based on similar projects):

XS (Extra Small): 1-2 man-weeks
   Example: Simple CRUD module, Basic form

S (Small): 2-4 man-weeks
   Example: User authentication, Basic reporting

M (Medium): 1-2 man-months
   Example: Complex module with workflow, Integration API

L (Large): 2-4 man-months
   Example: Core business logic, Advanced dashboard

XL (Extra Large): 4-6 man-months
   Example: Complete subsystem, Complex integration

Apply to Epics:

┌─────────────────────────────┬──────┬─────────────┐
│ Epic/Component              │ Size │ Effort      │
├─────────────────────────────┼──────┼─────────────┤
│ User Management             │  M   │ 1.5 months  │
│ Core Feature A              │  L   │ 3 months    │
│ Core Feature B              │  M   │ 2 months    │
│ Integration Module          │  L   │ 3 months    │
│ Admin Panel                 │  M   │ 1.5 months  │
│ Reporting System            │  M   │ 2 months    │
│ Infrastructure & DevOps     │  S   │ 1 month     │
├─────────────────────────────┼──────┼─────────────┤
│ SUBTOTAL                    │      │ 14 months   │
└─────────────────────────────┴──────┴─────────────┘

BƯỚC 3: Three-Point Estimation (1 giờ)

Áp dụng PERT cho mỗi Epic:

Formula: Expected = (Optimistic + 4×Most_Likely + Pessimistic) / 6

Example cho "Core Feature A":
┌──────────────────┬─────────────┐
│ Optimistic       │ 2 months    │
│ Most Likely      │ 3 months    │
│ Pessimistic      │ 5 months    │
├──────────────────┼─────────────┤
│ PERT Estimate    │ 3.2 months  │
│ Standard Dev     │ 0.5 months  │
└──────────────────┴─────────────┘

Complete Estimation Table:

┌─────────────────────┬──────┬────────┬────────┬──────────┬────────┐
│ Epic                │ Opt  │ Likely │ Pess   │ PERT Est │ StdDev │
├─────────────────────┼──────┼────────┼────────┼──────────┼────────┤
│ User Management     │ 1.0  │ 1.5    │ 2.5    │ 1.6      │ 0.25   │
│ Core Feature A      │ 2.0  │ 3.0    │ 5.0    │ 3.2      │ 0.50   │
│ Core Feature B      │ 1.5  │ 2.0    │ 3.5    │ 2.2      │ 0.33   │
│ Integration         │ 2.0  │ 3.0    │ 5.0    │ 3.2      │ 0.50   │
│ Admin Panel         │ 1.0  │ 1.5    │ 2.5    │ 1.6      │ 0.25   │
│ Reporting           │ 1.5  │ 2.0    │ 3.0    │ 2.1      │ 0.25   │
│ Infrastructure      │ 0.5  │ 1.0    │ 2.0    │ 1.1      │ 0.25   │
├─────────────────────┼──────┼────────┼────────┼──────────┼────────┤
│ TOTAL (Development) │      │        │        │ 15 months│        │
└─────────────────────┴──────┴────────┴────────┴──────────┴────────┘

BƯỚC 4: Add Contingency & Other Activities

┌────────────────────────────────────┬──────────┬────────┐
│ Activity                           │ Effort   │ % Base │
├────────────────────────────────────┼──────────┼────────┤
│ Development (from PERT)            │ 15.0 mon │ 100%   │
├────────────────────────────────────┼──────────┼────────┤
│ + Project Management               │  1.5 mon │  10%   │
│ + Business Analysis/Clarification  │  2.0 mon │  13%   │
│ + Testing & QA                     │  3.0 mon │  20%   │
│ + UAT Support                      │  1.0 mon │   7%   │
│ + Documentation                    │  0.8 mon │   5%   │
│ + Deployment & Training            │  0.5 mon │   3%   │
├────────────────────────────────────┼──────────┼────────┤
│ SUBTOTAL                           │ 23.8 mon │        │
├────────────────────────────────────┼──────────┼────────┤
│ + Contingency Reserve (15%)        │  3.6 mon │  15%   │
│ + Management Reserve (10%)         │  2.4 mon │  10%   │
├────────────────────────────────────┼──────────┼────────┤
│ TOTAL EFFORT                       │ 29.8 mon │        │
└────────────────────────────────────┴──────────┴────────┘

BƯỚC 5: Resource Planning & Pricing

Team Composition:
Giả định triển khai 8 tháng và phân bổ FTE theo từng tháng. FTE tháng cao nhất là 6.7 FTE
Overlap & Coordination (≈15-20%). Khi nhiều người làm việc song song:

Daily standups
Code reviews
Integration meetings
Knowledge sharing
Coordination overhead Example: Pure coding: 10 man-months With 3 people: 4 months × 3 = 12 man-months (+20%)

Ramp-up Time (≈10%) New team members cần thời gian:

Onboarding
Code base familiarization
Domain knowledge transfer
Tool setup

Each person: 1-2 weeks không productive 2 Sr.Dev + 2 Mid.Dev = 4 people × 1.5 weeks = 6 weeks ≈ 3 man-months overhead

Mức an toàn , dự phòng: 8FTE


┌─────────────────────┬─────────┬──────────┬──────────┐
│ Role                │ Members │ Duration │ Effort   │
├─────────────────────┼─────────┼──────────┼──────────┤
│ Project Manager     │ 0.5     │ 8 months │ 4 months │
│ Business Analyst    │ 1       │ 6 months │ 6 months │
│ Tech Lead/Architect │ 1       │ 8 months │ 8 months │
│ Senior Developer    │ 2       │ 7 months │ 14 month │
│ Middle Developer    │ 2       │ 6 months │ 12 month │
│ QA Engineer         │ 1       │ 5 months │ 5 months │
│ DevOps Engineer     │ 0.5     │ 4 months │ 2 months │
├─────────────────────┼─────────┼──────────┼──────────┤
│ TOTAL               │ 8 FTE   │ 8 months │ 51 m-mon │
└─────────────────────┴─────────┴──────────┴──────────┘

Note: 51 man-months / 8 months = ~6.4 average team size
      Tổng effort cao hơn 29.8 do overlap và ramp-up

III. TEMPLATE BÁO GIÁ CHO KHÁCH HÀNG

Option A: Fixed Price with Range

PROPOSAL SUMMARY
================

Project Duration: 7-9 months
Team Size: 6-8 members

PRICING OPTIONS:

Option 1: FIXED PRICE
┌──────────────────────────────────────────────────┐
│ Total Project Cost: $XXX,XXX - $XXX,XXX          │
│                                                  │
│ Payment Milestones:                              │
│ - Contract signing (20%):    $XX,XXX            │
│ - Design approval (15%):     $XX,XXX            │
│ - Development Phase 1 (25%): $XX,XXX            │
│ - Development Phase 2 (25%): $XX,XXX            │
│ - UAT & Go-live (15%):       $XX,XXX            │
└──────────────────────────────────────────────────┘

Scope: Based on agreed Epic-level requirements
Out of Scope: [List clearly]
Change Requests: Handled separately after formal CR process

Option B: Time & Material with Cap

Option 2: TIME & MATERIAL (with ceiling)
┌──────────────────────────────────────────────────┐
│ Rate Card:                                       │
│ - Project Manager:    $XX/hour                   │
│ - Tech Lead:          $XX/hour                   │
│ - Senior Developer:   $XX/hour                   │
│ - Middle Developer:   $XX/hour                   │
│ - QA Engineer:        $XX/hour                   │
│                                                  │
│ Estimated Range: $XXX,XXX - $XXX,XXX             │
│ Not-to-Exceed Cap: $XXX,XXX                      │
│                                                  │
│ Billing: Monthly based on actual hours           │
└──────────────────────────────────────────────────┘

Option C: Phased Approach (RECOMMENDED)

Option 3: PHASED DELIVERY ⭐ RECOMMENDED
┌──────────────────────────────────────────────────┐
│ PHASE 1: Discovery & Design (Fixed)              │
│ Duration: 4-6 weeks                              │
│ Cost: $XX,XXX                                    │
│ Deliverables:                                    │
│ - Detailed Requirements Document                 │
│ - System Architecture                            │
│ - UI/UX Design                                   │
│ - Detailed Project Plan & Estimate               │
│                                                  │
│ PHASE 2: Development (T&M with cap)              │
│ Duration: 5-7 months                             │
│ Estimated Cost: $XXX,XXX - $XXX,XXX              │
│ Based on Phase 1 detailed estimate               │
│                                                  │
│ TOTAL INVESTMENT: $XXX,XXX - $XXX,XXX            │
└──────────────────────────────────────────────────┘

Benefits:
✓ Reduced risk for both parties
✓ More accurate Phase 2 estimate
✓ Flexibility to adjust scope
✓ Early exit option after Phase 1

IV. ASSUMPTIONS & RISKS DOCUMENT

Bắt buộc kèm theo báo giá:

ASSUMPTIONS

===========

Requirements are based on initial discussions dated [DATE]
Technical stack: [List technologies]
Team availability: Start date [DATE]
Client provides timely feedback (within 2 business days)
Access to necessary systems/data provided by client
Third-party services are available and accessible
No major scope changes during development

EXCLUSIONS

==========

Mobile applications (Web only)
Integration with System X (unless API documented)
Data migration from legacy system
Post-launch maintenance (separate contract)
Training (more than 2 sessions)

RISKS & MITIGATION

==================

Risk	Impact	Mitigation
Unclear requirements	High	Phase 1 Discovery
Third-party API issues	Medium	Early integration
esource availability	Medium	Backup team ready
Scope creep	High	ormal CR process

DEPENDENCIES

============

Client to provide: [List]
Sign-off timeline: [Timeline]
Environment access: [Timeline]


## V. CÔNG CỤ HỖ TRỢ NHANH

### **Quick Estimation Spreadsheet Template**

Sheet 1: Epic Breakdown
┌─────┬──────────────┬──────┬─────┬────────┬──────┬──────────┐
│ ID  │ Epic         │ Size │ Opt │ Likely │ Pess │ PERT Est │
├─────┼──────────────┼──────┼─────┼────────┼──────┼──────────┤
│ E1  │ [Epic Name]  │  M   │  1  │   1.5  │  2.5 │   1.6    │
│ E2  │ [Epic Name]  │  L   │  2  │   3    │  5   │   3.2    │
└─────┴──────────────┴──────┴─────┴────────┴──────┴──────────┘

Sheet 2: Resource Planning
┌──────────────┬─────┬──────────┬────────┬──────┐
│ Role         │ Qty │ Duration │ Rate   │ Cost │
├──────────────┼─────┼──────────┼────────┼──────┤
│ [Role]       │  2  │ 6 months │ $X,XXX │ $XXX │
└──────────────┴─────┴──────────┴────────┴──────┘

Sheet 3: Pricing Calculator
- Auto-calculate totals
- Apply contingency
- Generate price ranges

One-Page Estimator (For Quick Reference)

QUICK ESTIMATION CHECKLIST

□ List all major features (Epic level)
□ Compare with similar past projects
□ Apply T-shirt sizing
□ Calculate PERT estimates
□ Add standard activities (PM, QA, BA)
□ Add 15-25% contingency
□ Define team composition
□ Calculate duration (effort/team size)
□ Add 10-20% for unknowns
□ Create 3 pricing options
□ Document assumptions
□ List exclusions clearly
□ Identify key risks

SANITY CHECK: □ Does timeline make sense?
□ Is team size realistic?
□ Compared with industry benchmarks?
□ Buffer adequate for unknowns?

VI. BENCHMARKS THAM KHẢO

TYPICAL PROJECT RATIOS:
=======================

Development:          50-60% of total effort
Testing:              15-20%
Project Management:   8-12%
Business Analysis:    10-15%
Documentation:        3-5%
Deployment:           2-5%

TEAM PRODUCTIVITY:
Developer output:     5-10 function points/month
                     or 100-200 LOC/day (quality code)

CONTINGENCY:
Known risks:          10-15%
Unknown risks:        10-15%
High uncertainty:     20-30%

VII. LỜI KHUYÊN

✅ DO's:

Always provide a range, không báo giá số tròn duy nhất
Recommend phased approach - giảm rủi ro cho cả 2 bên
Document everything - assumptions, exclusions, dependencies
Include buffer - 25-35% tổng cho high-level requirements
Reference past projects - tăng độ tin cậy
Clarify change process - tránh scope creep

❌ DON'Ts:

Không commit fixed price khi yêu cầu quá mơ hồ
Không quên các hidden tasks (meetings, setup, deployment)
Không low-ball để win deal - sẽ thua lỗ sau
Không ignore risks và dependencies
Không estimate một mình - cần input từ tech team

🎯 Best Practices:

1. Quick Workshop (4 hours):
   - Gather key stakeholders
   - Epic breakdown session
   - T-shirt sizing
   - Risk identification

2. Use Templates:
   - Standardized estimation sheet
   - Proposal template
   - Assumption checklist

3. Validate:
   - Check với tech lead
   - Compare với past projects
   - Sanity check timeline
   - Review với senior PM

4. Present Options:
   - Option A: Conservative (higher price, lower risk)
   - Option B: Aggressive (lower price, higher risk)
   - Option C: Phased (recommended)

VIII. EMAIL MẪU GỬI KHÁCH HÀNG

Subject: Proposal - [Project Name] Estimation

Dear [Client Name],

Thank you for the opportunity to propose on [Project Name].

Based on our discussions and the high-level requirements 
provided, please find attached our proposal with following 
options:

RECOMMENDED APPROACH: Phased Delivery
- Phase 1 (Discovery): 4-6 weeks, $XX,XXX (Fixed)
- Phase 2 (Development): 5-7 months, $XXX,XXX-$XXX,XXX

This approach allows us to:
✓ Provide detailed requirements and accurate estimate
✓ Reduce risks for both parties
✓ Ensure alignment before major investment

ALTERNATIVE: Fixed Price
- Total: $XXX,XXX - $XXX,XXX
- Timeline: 7-9 months
- Based on assumptions documented

Key Points:
• Estimates based on current understanding
• Subject to detailed analysis in Phase 1
• Includes 20% contingency for unknowns
• Excludes [list major exclusions]

Next Steps:
1. Review proposal and assumptions
2. Schedule call to discuss questions
3. Refine scope if needed
4. Proceed with Phase 1 or sign-off

I'm available [dates/times] to discuss.

Best regards,
[Your Name]

Tổng kết: Trình tự:

⏱️ 2-4 giờ: Epic breakdown + T-shirt sizing
⏱️ 1-2 giờ: Three-point estimation
⏱️ 1 giờ: Resource planning + pricing
⏱️ 1 giờ: Document assumptions + create proposal

Total: 5-8 giờ để có một báo giá chuyên nghiệp và có căn cứ.

Agile Software Development capstone project