Test Estimation Techniques

What are way to estimate?

There are several test estimation techniques that can be used in software testing projects, including:

  1. Expert judgment: This involves getting input and estimates from experienced testers and subject matter experts who have worked on similar projects in the past. Expert judgment can be used to estimate testing effort, timelines, and resource needs.
  2. Analogous estimation: This technique involves using historical data from previous testing projects to estimate the effort and resources required for the current project. This can be useful when the current project is similar in size and complexity to a previous project.
  3. Bottom-up estimation: This involves breaking down the testing effort into smaller, more manageable tasks and estimating the effort required for each task. The estimates for each task are then added up to get an overall estimate for the testing effort.
  4. Three-point estimation: This technique involves using three estimates for each testing task - optimistic, most likely, and pessimistic. These estimates are then used to calculate the expected time and effort required for each task.
  5. Wideband Delphi: This technique involves getting input from a group of experts through a series of rounds of estimation and feedback. The estimates are refined in each round until a consensus is reached on the overall testing effort.
  6. Function Point Analysis: This technique involves analyzing the software requirements and using a formula to estimate the testing effort based on the number of function points in the requirements.
  7. Test Points: This technique involves assigning points to different testing activities based on their complexity and effort required. The points are then used to calculate the overall testing effort.

Each of these techniques has its strengths and weaknesses, and the choice of technique will depend on the specific needs and constraints of the testing project. It is important to use a combination of techniques and to refine estimates as more information becomes available during the testing project.

Examples:

How the different test estimation techniques can be applied in a software test planning template:

  1. Expert judgment:
  • Identify experienced testers and subject matter experts who can provide input on the testing effort, timelines, and resource needs.
  • Schedule meetings or interviews to gather their estimates and input.
  • Document the input and estimates provided by each expert.
  1. Analogous estimation:
  • Identify previous testing projects that are similar in size and complexity to the current project.
  • Collect data on the testing effort, timelines, and resource needs for those projects.
  • Use that data to estimate the testing effort, timelines, and resource needs for the current project.
  1. Bottom-up estimation:
  • Break down the testing effort into smaller, more manageable tasks.
  • Estimate the effort required for each task.
  • Document the estimates for each task and add them up to get an overall estimate for the testing effort.
  1. Three-point estimation:
  • For each testing task, gather three estimates - optimistic, most likely, and pessimistic.
  • Calculate the expected time and effort required for each task based on those estimates.
  • Document the estimates and expected values for each task.
  1. Wideband Delphi:
  • Identify a group of experts who can provide input on the testing effort, timelines, and resource needs.
  • Schedule multiple rounds of estimation and feedback sessions.
  • Refine the estimates in each round until a consensus is reached on the overall testing effort.
  1. Function Point Analysis:
  • Analyze the software requirements to identify the number of function points.
  • Use a formula to estimate the testing effort based on the number of function points.
  • Document the formula and estimated testing effort.
  1. Test Points:
  • Assign points to different testing activities based on their complexity and effort required.
  • Use the points to calculate the overall testing effort.
  • Document the points assigned to each testing activity and the overall testing effort calculated.

These templates can be used as a starting point and customized to fit the specific needs of the testing project. It is important to continually refine and update the estimates as more information becomes available and the project progresses.

Meet John

John was a Test Manager at a software development company. He was tasked with estimating the testing effort required for the next release of their product. John knew that estimating testing effort was crucial for the project's success, and he wanted to use the best techniques available.

John decided to start by using the Wideband Delphi technique. He gathered a team of experts, including testers, developers, and business analysts, and asked them to provide their estimates. Each member gave their estimate privately, and John aggregated the results. They discussed the discrepancies and re-estimated until they reached a consensus.

John then decided to use the Three-Point Estimation technique to get more accurate estimates. He asked his team to provide three estimates for each testing task: the best-case scenario, the most likely scenario, and the worst-case scenario. John then used a formula to calculate the expected value for each task, which would give him a more accurate estimate.

Next, John decided to use the Test Point Analysis technique to estimate the testing effort required for each test case. He assigned points to each test case based on their complexity and estimated the number of hours required to execute each test case based on the point value. This technique helped John to allocate testing resources efficiently and prioritize the testing effort.

Finally, John decided to use the expert judgment technique to validate his estimates. He asked other Test Managers in his network to review his estimates and provide feedback. He also consulted with industry experts to get their opinions on his approach.

John used a combination of different estimation techniques to get the most accurate estimates for his testing effort. He knew that estimating testing effort was not an exact science and that there were many factors that could affect the outcome. By using different techniques, John was able to minimize the risks of inaccurate estimates and ensure the success of his project.