➡️Software Test Estimation Techniques:-
- “Software test estimation techniques help predict the effort, time, and cost involved in testing a software product accurately.”
- “Proper test estimation techniques reduce project risks and ensure better resource planning in software testing.”
- “Test estimation is a critical phase that directly influences the success of software testing and overall product quality.”
➡️Introduction:
Software test estimation is a critical activity in test management that predicts the time, effort, and cost required to complete testing tasks. Accurate estimations help organizations deliver high-quality software within deadlines and budgets. In this guide, we will explore the importance of test estimation, what to estimate, popular techniques, and best practices for precise predictions.
➡️Why is Software Test Estimation Important?
When initiating a testing project, two common questions from clients are:
- How long will it take?
- How much will it cost?
For small projects, answering is relatively easy. However, for larger projects, like testing a complex banking website, a systematic estimation approach is essential. Correct estimation ensures realistic planning, resource allocation, and stakeholder confidence.
➡️What to Estimate in a Testing Project?
When preparing a test estimation, you should consider:
- Resources: People, tools, and infrastructure needed to complete tasks.
- Time: The duration required to complete each task.
- Human Skills: The expertise and experience of the testing team members.
- Cost: The overall project budget.
Understanding these components helps in creating accurate, realistic test estimations.
➡️Popular Software Test Estimation Techniques:-
1. Work Breakdown Structure (WBS):
WBS is a technique where the entire testing project is broken down into smaller, manageable tasks and subtasks. For example:
| Task | Subtask |
|---|---|
| Analyze Requirements | Study SRS, interview stakeholders |
| Create Test Specification | Design scenarios, write test cases |
| Set Up Test Environment | Build infrastructure |
| Execute Test Cases | Perform testing, log results |
| Report Defects | Record and report issues |
2. Function Point/Testing Point Analysis:
In this method, tasks are sized based on system functionalities:
- Simple Functions: Weight = 1
- Medium Functions: Weight = 3
- Complex Functions: Weight = 5
Suppose a website has:
| Complexity | Count | Total Weight |
|---|---|---|
| Simple | 4 | 4 |
| Medium | 5 | 15 |
| Complex | 3 | 15 |
Total Function Points = 34
If 1 function point = 5 hours, total effort = 170 hours.
This method gives an objective way to estimate time based on functional complexity.
3. Three-Point Estimation:
Three scenarios are considered:
- Best Case (O): Minimal time (e.g., 120 hours)
- Most Likely Case (M): Normal time (e.g., 170 hours)
- Worst Case (P): Maximum time (e.g., 200 hours)
The estimated effort (E) is calculated as:
E = (O + 4M + P) / 6
E = (120 + 4×170 + 200) / 6 = 166.6 hours
Thus, the task “Create Test Specification” could take around 166.6 hours with ±13.3 hours variation.
4-Step Process to Estimate Testing Effort:
- Break Down the Project:
Divide the project into detailed tasks using WBS. - Assign Resources:
Allocate tasks to team members based on skills. - Estimate Effort for Each Task:
Use Function Point Analysis or Three-Point Estimation. - Validate with Management:
Review and approve the final estimation with stakeholders.
➡️Test Estimation Best Practices:-
- Add Buffer Time:
Always plan extra time for unexpected delays. - Account for Resource Availability:
Consider holidays, leaves, and part-time staff availability. - Use Past Experience:
Leverage data from previous similar projects to refine estimates. - Review and Adjust Estimates:
Revisit and update estimates during project execution if necessary. - Stick to Original Estimations:
Only adjust estimates when there are major scope changes.
➡️Common Estimation Models in Practice:-
- Bottom-Up Approach:
Estimation starts from the smallest tasks upwards, ensuring detailed accuracy. - Top-Down Approach:
Based on past experience, estimating effort at a higher level, then breaking it down. - Average Effort per Test Case:
Using historical averages (like X hours per test case) to calculate effort. - Wideband Delphi Method:
Expert-based consensus method involving iterative discussions. - Use-Case Point Method:
Based on the number and complexity of use cases. - Percentage Distribution:
Assign effort percentages to different phases (e.g., 30% design, 50% execution, etc.). - Ad-Hoc Method:
Quick estimation based on intuition and rough experience.
Previous Post: Use Case Testing in Software Engineering:-
➡️Conclusion:-
Software test estimation is both an art and a science. It requires analytical skills, domain knowledge, and practical experience. By applying structured techniques like WBS, Function Point Analysis, and Three-Point Estimation, project managers can provide more reliable delivery timelines and costs. Moreover, following best practices like adding buffers and using historical data ensures better predictability and client satisfaction.
A well-estimated testing effort not only reduces project risks but also builds a strong reputation for the QA team and the organization.
