SQE(Lecture 9)

8/6/2019 SQE(Lecture 9)

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In-Process Quality Metrics

In-Process quality metrics used to measure product

during development process.

In this metrics we will discuss the following.

1. Defect arrival pattern during testing.

2.

Phase based defect removal pattern.3. Defect removal effectiveness.


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Defect arrival pattern during testing

To measure defect arrival pattern, we have to

consider three different metrics.

The defect arrivals (defects reported) during the

testing phase by time interval (e.g., week). These arethe total arrival defects, not all of which are valid

defects.

The pattern of valid defect arrivals.

The pattern of defect backlog (Process all the defects

at the end of the development cycle. Generally

retesting (regression test) is needed to ensure that

targeted product quality levels are reached.


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Phase based defect removal pattern

It requires the tracking of defects at all phases of the

development cycle, including the design reviews,

code inspections, and formal verifications beforetesting.

The pattern of phase-based defect removal reflects the

overall defect removal ability of the developmentprocess.


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Project A


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Project B


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Defect Removal effectiveness

Defect removal effectiveness (or efficiency) can be

defined as follows:

DRE= (Defects removed during a developing phase)/(Total defects in the product) *100.

The denominator of the metric can only be approximated. It

is usually estimated by:

Defects removed during the phase + defects found

later


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The higher the value of the metric, the more effective

the development process and the fewer the defects

escape to the next phase or to the field.

Based on this metric, action plans to improve the

effectiveness of these phases were established and

deployed.


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Phase effectiveness of a software project


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Metrics for software maintenance

This metric is used after the development of asoftware product is complete and it is released to themarket.

During the maintenance phase the main thing is tofix the defects as soon as possible with excellent fixquality.

During the maintenance phase the following metricsare very important.


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Fix backlog and backlog management index.

Fixed response time.

Fix quality.


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Fix backlog and backlog

management index.

Fix backlog: It is a simple count of reported

problems that remain at the end of each monthor each week.

It is related to the rate of defect

arrivals and the rate at which fixes for reported

problems become available.


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Backlog management index:

BMI=(Number of problems closed (or solved) during the

month)/ Number of problems arrivals during the

month * 100%

BMI > 100 ---> Backlog is reduced.

BMI < 100 ---> Backlog is increased.


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Mean BMI is 102.9 means capability of the fix process is

functioning normally


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Quality Indicator classification

Quality indicator is classified as follows

Software Quality Assurance Plan.

Software Assessment Plan.

Quality Review. Supporting Methods &Techniques


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Software quality assurance plan includes SQA

tasks, its management in relation with the

development plan.

Software Assessment Plan includes all new

constraints with change environment, its reusability

along with security plans and its configuration.


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Quality Review Mechanism support to reduce all

review efforts and improve quality control including

continuous processes inspection.

Supporting Methods and Techniques includes

quality monitoring its complexity and sensitivity

issues.


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Fix Quality

Fix quality means number of defective fixes is

another important quality metric for the maintenance

phase.

A fix is defective if it did not fix the reported

problem, or if it fixed the original problem but

injected a new defect.


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The metric of percent defective fixes is simply the

percentage of all fixes in a time interval (e.g., 1

month) that are defective.

A defective fix can be recorded in two ways, record it

in the month it was discovered or record it in the

month the fix was delivered.


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Fixed Response Time

The fix response time metric is the Mean time of all

problems from open to closed.

EX: For many software development organizations,guidelines are established on the time limit within

which the fixes should be available for the reported

defects.

The response time for fixing will vary according to the

problems.

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SQE(Lecture 9)