Quality planning

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These slides contain topics covered in lecture of quality planning. …

These slides contain topics covered in lecture of quality planning.

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Transcript

  • 1. Quality Planning
  • 2. Introduction
    • “ Quality must be defined and measure if improvement is to be achieved.”
    • Facts about quality:-
      • Quality is a multidimensional concept
      • Their is a level of abstraction(depends on individual).
    • We should not treat quality measurement as the last step (before delivery and after assembly/development)
    • Like effort and schedule estimated we can estimate quality.
    • Software Quality
    • Quality is recognized as lack of “bugs” in the product(i.e conformance to requirements)
    • The above statement can be expressed by two ways:
      • Defects rate (number of defects per million LOC , per function point etc)
      • Reliability rate (number of failures per n hours of operations, mean time to failure etc)
  • 3. Cont..
    • Quality is measured with customer satisfaction
    • For instance IBM monitors satisfaction with its s/w CUPRIMSO(capability[functionality],usability,performance,reliability,install-ability,maintainability,documentation,service, and overall).
    • Hwelett-Packard focused on FURPS(functionality,usability,reliability,performance and serviceability).
    • Quality attributes depends upon the type of software and customers we have.
    • Further topic deals with “how a project manager set the quality goal for their project and plan to achieve that goal.”
  • 4. Quality Concept
    • The ultimate goal of the project manager is to ensure that the final s/w is of high quality.
    • How to define software quality? (as s/w has so many quality characteristics)
    • First understand Defect Injection and Removal Cycle.
      • Errors are obvious – S/w involves so many people for long duration of time
      • Defects Injection stages – all the transformation stages(analysis,design coding testing)
      • The high quality s/w must remove these defects
      • We have introduce defects removal after each transformation stage.
    Requirement Analysis R Design R Coding R UT IT/ST AT Defects Removal Defects Injection
  • 5. Quality Management
    • Defects removal managed by quality management.
      • Quality management is to plan suitable quality control activities and then properly execute and control them to achieve the project's quality goals.
    • Procedural approach to quality management
    • The defects are detected by performing reviews or testing.
    • In procedural approach we define the procedures for testing or review.
    • This method could not able to provide the quantitative measurement of quality , just provide the project manager is that whether the quality control task are executed or not.
    • Quantitative approaches to quality management
    • For better assessment of quality we require metrics data for evaluation.
    • It not only execute the quality control procedure but also looks at metrics data to evaluate effectiveness of quality control activities.
  • 6. Cont..
    • Quantitative quality management has following two aspects :-
      • Setting a quantitative goal
      • Then managing the software development process quantitatively (so that this quality goal is met with a high degree of confidence)
    • Early warning signs
  • 7. Cont.
    • Approaches can be used for quantitative quality control
      • Software Reliability Models
        • It use the failure data during the final stage of testing
        • Use to estimates the reliability of the software
        • It indicates whether the reliability is accepted or more testing is required
        • Not provide intermediate goals for the early detection
      • Defects Removal Efficiency (DRE)
        • In QC activity DRE can be defined as the % of existing total defects that are detected by the QC activity.
          • DREi=Ei)/(Ei+Ej)
        • It is carried out in full life cycle of the project before the s/w is delivered
  • 8. Cont.
      • Quality Prediction
        • Predict the defects as per the estimated defects level.
        • Process step has defect detection point
        • We find % of total defects detected at various detection stages
      • Statistical Process Control (SPC)
        • Set performance expectation of the various quality control processes (testing and reviews) in terms of control limits
        • If at any stage the actual number of defects are less than the target then it may be possible that the removal process was not executed properly
  • 9. Quantitative Quality Management Planning
    • It is a three step process perform my the project manager.
      • Setting the quality goal
      • Prediction of defect levels at intermediate milestones
      • Planning for suitable enhancements to the quality process
  • 10. Cont.
    • Setting the quality goal
      • Set during the planning stages by the project managers
      • Its noting but expected number defects found during acceptance testing (AT)
      • Their are two primary source for setting quality goal
        • Past data from similar projects
        • Data from the process capability baseline (PCB)
  • 11. Quality Goal
    • If we uses past data from similar projects approach then,
      • We can estimates the number of defects found in the current by following formula
        • Estimate for AT defects in CP=(AT defects in SP * estimated effort in CP)/Actual effort in SP
    • If use data from the PCB then(if we set the quality target as the number of defects per function point)
      • Sequence of steps as follows :-
        • 1) set the quality goal in terms of defects per FP.
        • 2) Estimate the expected productivity level for the project.
        • 3) Estimate the size of FP as (expected productivity * estimated effort )
        • 4) Estimate the number of AT defects as (quality goal * estimated size)
      • Productivity is a ratio of what is produced to what is required to produce it.
  • 12. Quality Goal
    • Sometime it is more useful to set the target in terms of the process's defects removal efficiency.
    • Set as follows:
        • Set the quality goal in terms of defect removal efficiency.
        • Estimate the total number of defects from the defect injection rate and estimated size,or by the effort-based defect injection rate and the effort estimate.
        • Estimate the number of AT defects from the total number of defects and quality goal.
  • 13. Quality Process Planning
    • It all about the setting the quality goal of the current project with respect to the similar project.
    • Two main task of quality control
      • Review -> need good review process (By PM)
      • Testing -> need good testing method (By PM)
  • 14. Defects Prevention Planning
    • Defects prevention (DP) activities are intended to improve quality and improve productivity.
    • For a given process and its removal efficiency, the quality of the final delivered software can be improved if fewer defects are introduced while the s/w is being built.
    • DP also has productivity benefits [How]
        • Its a cycle of defects injection and remove ...without adding any value to the software.
  • 15. How
    • How is DP done ?
        • The premise of the DP is that there is some cause behind the injected defects.
    • To implement DP
      • A project manager may start with the set of
        • recommendations available at the organization level and
        • recommendations based on analysis of the project's defect data
  • 16. Defect prevention steps At Infosys
    • Identify a defect prevention team within the project.
    • Have a kick-off meeting and identify existing solutions.
    • Plan for defect prevention.
      • Set defect prevention goals for the project.
      • See that the DP team is trained on DP and causal analysis, if needed.
      • Define the frequency at which defect prevention activities will be carried out.
    • · Do defect prevention.
      • At defined points, collate defects data.
      • Identify the most common types of defects by doing Pareto analysis.
      • Perform causal analysis and prioritize the root causes.
      • Identify and develop solutions for the root causes.
      • Implement the solutions.
      • Review the status and benefits of DP at the project milestones.
    • Capture learning.
  • 17. Case Study
    • Read Case study given in
      • Book :- Software Project Management in Practice
        • By Panjak Jalote