Software Test Estimation Techniques & Best Practices

Test estimation techniques refer to the methods and approaches used to determine or estimate the effort, time, and resources required for testing activities in software development projects.

Estimating the testing effort is crucial for effective project planning, resource allocation, and scheduling.

What is Software Test Estimation?

Software test estimation is a managerial task that involves assessing and approximating the required time, resources, and costs for executing tests in a specific environment. It serves as a projection that aids in preventing time constraints and exceeding budgets. 

Why Test Estimation?

Test estimation is conducted for several important reasons:

• Project Planning: With correct estimations done, the overall project timeline can be kept under check. Project managers can create realistic schedules and allocate resources as per need if they know the time required for testing activities well in advance. This allows for effective coordination with development and other project activities.
  
• Resource Allocation: With test estimations in place, the resource allocations: namely number of testers, testing tools, and testing environments required, can be allocated diligently and efficiently. It helps to ensure that overallocation or underutilization of resources is avoided.
  
• Budgeting and Cost Control: Budgets are crucial to any project’s success. Expenses like  personnel costs, infrastructure costs, and tooling costs can be estimated well if testing efforts are estimated efficiently. By having a clear understanding of the expected costs, organizations can create accurate budgets, monitor expenses, and prevent cost overruns.
  
• Risk Management: Estimation can also help build visibility into any potential risks associated with testing including areas that may require additional attention or resources. This allows for risk mitigation strategies to be implemented proactively.
  
• Stakeholder Expectations: Estimation helps set realistic expectations with project stakeholders, including clients, managers, and development teams.

• Project Optimization: Accurate estimation allows for better planning and optimization of testing activities. It helps identify opportunities for process improvements, resource optimization, and automation, leading to increased efficiency and productivity in the testing process.

What to estimate?

Estimation techniques are employed to estimate various aspects of software development projects. These techniques are used to estimate the effort, time, resources, and costs associated with different project components. 

1. With estimation techniques, one can estimate the effort required for activities such as analysis, design, coding, testing, documentation, and project management. 
2. They help in estimating the time required to complete the project or specific milestones, considering dependencies and constraints.
3.  Estimation techniques also assist in estimating the resources needed, including team members, their skills, tools, and infrastructure. 
4. Additionally, these techniques can be applied to estimate the complexity of features and functionalities, identify potential risks and uncertainties, and estimate the effort required for testing, documentation, and other project activities. 

Test Estimation Techniques

Following is a list of most common but widely used test estimation techniques:

Estimation Techniques	Brief introduction
Work Breakdown Structure	It is a method of breaking down large tasks into smaller, easily executable groups
3-Point Software Estimation Test	Tasks are broken down into smaller tasks, and then each task is estimated based on 3 points – Best case, Most likely and Worst case estimates
Wideband Delphi Method	It is a technique where an expert set of panel comes together to determine the most probable outcome and they have a common consensus
Functional Point Analysis	Large tasks are broken down into small tasks. Each small task is then estimated based on size, cost and duration of project
Agile Estimation	In these techniques, the current data and past  experience are used for estimation and new information is continuously integrated into the project to refine the process of estimation
Distribution in Percentage	Here, every stage is assigned or assessed in terms of percentages. This is to find how much effort should be put into each stage of the testing cycle.

Test estimation best practices

Test estimation is a critical aspect of the software development cycle. Accurate estimation helps in planning, resource allocation, and project management. Here are some best practices for test estimation:

• Understand Requirements: You should have a thorough understanding of the project requirements before you begin estimating. Any ambiguities or incomplete requirements can lead to inaccurate estimates.
• Break Down Tasks: Rather than estimating the whole story as a single value, breakdown the testing effort into smaller, manageable tasks. This will make the estimation process more precise and will reduce the risk of overlooking important aspects.
• Use Historical Data: Sometimes historical data can help estimate better and faster. A similar story may have been estimated and worked upon earlier. Refer to past projects with similar scope and complexity to gain insights into the testing effort required. 
• Involve the Right Experts: Ask your team members if someone else has worked upon a similar story estimation. This input from experienced testers, test leads, and other stakeholders shall improve the accuracy of estimates.
• Use Estimation Techniques: Utilize the most suitable technique based on the project’s characteristics.
• Consider Risk Factors: Any potential risks that may impact testing efforts should be identified in the beginning. Factor in additional time for handling unforeseen issues that could arise during testing.
• Account for Environment and Infrastructure: Ensure that the required test environments, tools, and infrastructure are considered in the estimation. Setting up and maintaining these resources can take time.
• Review and Validate: A fresh eye can often see what a repetitive eye cannot see. Ask someone to review and this may help in better estimations.
• Update Estimations: As the project progresses and more information becomes available, reassess and update the estimates accordingly. Make sure you mention a reason for changing original estimation for any future reference.
• Track and Learn: Keep track of the actual time and effort spent on testing activities and compare them with the estimated values. Analyze any discrepancies and learn from them to improve future estimations.

Remember that estimation is not an exact science, and unforeseen circumstances can affect the actual effort required. Regularly revisit and adjust the estimates as the project progresses to ensure a successful testing phase.

Software Test Estimation Template

Here is a sample template to be used for software estimations.

Project Name: [Name of the Project]
Estimation Date: [Date of Estimation]
Estimation Prepared By: [Name of Estimator]
Estimation Reviewed By: [Name of Reviewer]
Project Overview:[Provide a brief overview of the project, its objectives, and scope.]
Test Scope:[List the in-scope items for testing, including modules, features, and functionalities.]
Test Types Included:[List the types of testing that will be performed, such as functional, regression, performance, security, etc.]
Assumptions:[List any assumptions made during the estimation process.]
Estimation Technique:[Specify the technique used for estimation (e.g., Expert Judgment, Three-Point Estimation, Delphi Technique, etc.)]
Contingency:[Specify any contingency effort included to account for unforeseen issues and risks.]
Dependencies:[List any dependencies that may impact the testing effort, such as availability of developers or test environment.]
Risks and Mitigation Strategies:[List potential risks related to testing and the strategies planned to mitigate them.]
Estimation Approval:[Include a section for relevant stakeholders to approve the estimation.]

Test Effort Breakdown
Test Activity	Estimated Effort (hours/days) |	Assumptions/Notes
Test Planning and Strategy
Test Case Design
Test Environment Setup
Test Data Preparation
Test Execution   -Functional -Regression -Performance -Security -Other
Defect Reporting and Tracking
Test Closure and Reporting
Total Estimated Test Effort

Summary

The test estimation techniques are not just useful for testing software but can be helpful for the entire software development life cycle. Above mentioned techniques can be combined with each other to get a much more precise estimation. Getting accurate estimation for any project is a vital step in using the resources, time, and skills to their maximum potential.

What is the 3-point estimation in testing? The Three-Point Estimation, also known as the PERT (Program Evaluation and Review Technique) estimation, is a technique used in project management, including testing, to provide a more realistic and reliable estimate for task durations or effort. In the context of testing, the Three-Point Estimation involves considering three estimates for each task:

• Optimistic Estimate (O): This is the best-case scenario estimate, assuming everything goes perfectly without any unexpected issues or delays.
• Most Likely Estimate (M): This is the estimate based on a realistic scenario, considering typical challenges and factors that might affect the task.
• Pessimistic Estimate (P): This is the worst-case scenario estimate, assuming various difficulties and potential delays come into play.

Using these three estimates, the PERT formula is applied to calculate the Expected Duration (ED) or Expected Effort (EE) for the task:
ED=(O+4M+P)/6
This formula places more weight on the “Most Likely Estimate” while incorporating the Optimistic and Pessimistic Estimates to balance out the influence of overly optimistic or pessimistic assumptions. How many test estimation techniques are available? There are several test estimation techniques available that project managers and teams can use to estimate the effort, time, and resources required for testing activities. Some of the commonly used test estimation techniques include:

• Expert Judgment
• Analogous Estimation
• Parametric Estimation
• Three-Point Estimation (PERT)
• Delphi Technique
• Wideband Delphi
• Work Breakdown Structure (WBS)
• Use Case Point Estimation
• Test Point Analysis
• Function Point Analysis
• Comparative Estimation
• Vendor Bid Analysis

These are just a few popular ones. Remember that each of these techniques has its strengths and weaknesses and may be more suitable for different project scenarios. Project managers often choose the technique that aligns with the project’s characteristics, available data, and team expertise.