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Test Estimation Techniques

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Test Estimation Techniques

  1. 1. Test Estimation Techniques…
  2. 2. What is Estimation? <ul><li>Is it a Science? </li></ul><ul><li>Is it art? </li></ul><ul><li>A bit of both - Design... </li></ul>
  3. 3. What is an Estimate ? <ul><li>An estimate is a forecast or prediction. </li></ul><ul><li>An Estimate is an approximation of what it would Cost. </li></ul><ul><li>A Rough Idea how long a Task would take to complete. </li></ul><ul><li>An Approximate calculation of Quantity or Degree or Worth. </li></ul>
  4. 4. How to measure - Estimate <ul><li>An Estimate is Effort required in terms of </li></ul><ul><ul><li>Time </li></ul></ul><ul><ul><li>Cost </li></ul></ul><ul><li>An Estimate is based on </li></ul><ul><ul><li>Past Experience/ Past Data </li></ul></ul><ul><ul><li>Available Documents/ Knowledge </li></ul></ul><ul><ul><li>Assumptions </li></ul></ul><ul><ul><li>Calculated Risks </li></ul></ul>
  5. 5. Why do we Estimate? <ul><li>Overshooting Budgets </li></ul><ul><li>Exceeding Timescales </li></ul><ul><li>Example of Overshooting Budgets and Timescales : </li></ul><ul><ul><li>A Standish Group survey of 8,000 software projects found that the average project exceeded its planned budget by 90 percent and its schedule by 120 percent . </li></ul></ul><ul><ul><li>Several industry studies have reported that fewer than half of software projects finish within their allotted schedules and budgets. </li></ul></ul>
  6. 6. Importance of Estimates Estimate too high Estimate too low Actual Schedule Estimated Schedule actual schedule = estimated schedule minimum actual schedule
  7. 7. Importance of Estimates Cont… <ul><li>A study conducted by KPMG Pete Marwick found these causes of software runaways: </li></ul><ul><li>Project Objectives Not Fully Specified (51%) </li></ul><ul><li>Bad Planning and Estimating (48%) </li></ul><ul><li>Technology New to the Organization (45%) </li></ul><ul><li>Inadequate/No Project Management Methodology (42%) </li></ul><ul><li>Insufficient Senior Staff on the Team (42%) </li></ul><ul><li>Poor Performance by Suppliers of Hardware/Software (42%) </li></ul>
  8. 8. <ul><li>Questions to be asked </li></ul><ul><li>Are the Requirements finalized? </li></ul><ul><li>If not then, How frequently the requirements change? </li></ul><ul><li>What are the Types of Testing required? </li></ul><ul><li>Are Test Assets already available? </li></ul><ul><li>If Test Assets are available, What Stage they are in ? </li></ul><ul><li>Is the Infrastructure for Testing ready? </li></ul><ul><li>Have the Assumptions/Risks been documented. </li></ul><ul><li>Are the Responsibilities clear. </li></ul>Estimation for Testing
  9. 9. Steps involved in Estimation Work out elapsed time / critical path Is the total reasonable Reassess tasks and / or effort Identify scope State assumptions Assess the tasks involved Estimate the effort for each task Calculate Total Effort No Yes Finish and Present the Estimate
  10. 10. Test Estimation Process <ul><li>Step 1 - Define Function Point </li></ul><ul><li>Step 2 - Give Weightage to all Function Points </li></ul><ul><li>Step 3 - Define an Estimate Per Function Point </li></ul><ul><li>Step 4 - Calculate Total Effort Estimate </li></ul>
  11. 11. Function Point Method <ul><li>What is a Function Point ? </li></ul><ul><ul><li>Function points are a measure of the size of computer applications and the projects that build them. </li></ul></ul><ul><ul><li>The size is measured from a functional, or user, point of view. </li></ul></ul><ul><ul><li>It is independent of the computer language, development methodology, technology or capability of the project team used to develop the application. </li></ul></ul><ul><li>Function Point can be based upon </li></ul><ul><ul><li>Use Cases </li></ul></ul><ul><ul><li>Test Scenarios/ Test Cases </li></ul></ul><ul><ul><li>Code </li></ul></ul>
  12. 12. Function Point Method – Step 1 <ul><ul><li>Define Function Points </li></ul></ul><ul><ul><li>Function Point is measured from a functional, or user, point of view. </li></ul></ul><ul><ul><li>It is independent of computer language, development methodology, technology or capability of the project team. </li></ul></ul><ul><ul><li>Based on Available Documents (SRS, Design etc.) </li></ul></ul><ul><ul><li>Also Based on Application knowledge and Application Domain </li></ul></ul><ul><ul><li>Can also be based upon Use Cases, Code, Test Scenarios </li></ul></ul>
  13. 13. Function Point Method – Step 2 <ul><ul><li>Give Weightage to all Function Points </li></ul></ul><ul><ul><li>Complex </li></ul></ul><ul><ul><ul><li>API/ Low level Interactions </li></ul></ul></ul><ul><ul><ul><li>Complex Batch Processes </li></ul></ul></ul><ul><ul><li>Medium </li></ul></ul><ul><ul><ul><li>Database Checks </li></ul></ul></ul><ul><ul><ul><li>Simple Batch Processes </li></ul></ul></ul><ul><ul><ul><li>Interaction between two or functionalities </li></ul></ul></ul><ul><ul><li>Simple </li></ul></ul><ul><ul><ul><li>GUI </li></ul></ul></ul><ul><ul><ul><li>Involving only One Functionality </li></ul></ul></ul>
  14. 14. Function Point Method – Step 3 <ul><ul><li>Define an Estimate Per Function Point </li></ul></ul><ul><ul><li>Based on similar Projects Experience. </li></ul></ul><ul><ul><li>Organization/Project Standards. </li></ul></ul>
  15. 15. Function Point Method – Step 4 <ul><ul><li>Total Effort Estimate = </li></ul></ul><ul><ul><li>Total Function Points * </li></ul></ul><ul><ul><li>Estimate defined Per Function Point </li></ul></ul>
  16. 16. Function Point Method - Example Medium Complex Simple Total Function Point Total 120 4.15 498 Weightage 1 3 5 Function Points 35 20 5 35 60 25 Estimate defined Per Function Point Total Estimated Effort( Person Hours)
  17. 17. To Conclude - Few Tips <ul><ul><li>Allow enough time to do a proper Project Estimate. </li></ul></ul><ul><ul><li>Use documented data from similar past Projects. </li></ul></ul><ul><ul><li>Use Own Estimates. </li></ul></ul><ul><ul><li>Use several different people to Estimate. </li></ul></ul><ul><ul><li>Re-Estimate the Project several times throughout its lifecycle. </li></ul></ul><ul><ul><li>Create a standardized estimation procedure. </li></ul></ul><ul><ul><li>Focus some effort on improving organization’s software Project estimation process. </li></ul></ul>
  18. 18. <ul><li>Define the scope </li></ul><ul><li>State your assumptions </li></ul><ul><li>Document your estimate </li></ul><ul><li>Assess if estimate is reasonable </li></ul><ul><li>Communicate - with requester and PM </li></ul><ul><li>Check actual effort against estimate </li></ul><ul><li>Use feedback next time </li></ul>Summary