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# Thread: Formula to find defect leakage for current release

1. ## Formula to find defect leakage for current release

Hi Mates,

I am new to Process Improvement and quality.I had a task which has to deliver total count of defect leakage
from phase to phase for the current release.I had a formula for getting the ratio of defect leakage from phase to phase
when i presented to the stake holders they said,formula uses the past data or the production data but it never returns the leakage for current release.

also informed me any metric which can capture this data will also be helpfull as a part testing process improvement project.

Read some pdf's and google docs but confused where to start or how to start.

any metric or formula to capture this will be helpfull to me.

2. ## Re: Formula to find defect leakage for current release

Defect Leakage can be calculated using

Defect Leakage = (A divided by (B-C))*100 i.e(A/(B-C))*100

Where
A = Total Defects found in production.
B = Total defect found in System Testing/ Regression or any STLC phase.
C = Total number of Invalid defects found during Phase "B".

3. ## Re: Formula to find defect leakage for current release

With regards to what your stakeholders said, first of all defect leakage or escaping defects (as I learned to call them a long time ago) can only be calculated after the project or stage are done and then you need to start keeping track for a significant amount of time to make sure you have a number of the number of bugs that escaped or leaked... If you immediately knew about the bugs that leaked you would have found them, right?

It is true that this is a great way to improve the process looking forward and I use it in most places I work in order to make sure we have "a constant learning process".

I wrote about how I work with this metric in my blog some time ago here - http://qablog.practitest.com/2008/01...aping-defects/

The formula I use is relatively straight forward and easy to understand:
Escaping defects rate = Escaping Defects / (Defects found in process + Escaping Defects)

Good Luck!

4. ## Re: Formula to find defect leakage for current release

Hey,

For the software metrics definition I suggest you to use Encyclopedia of Software Metrics.

I think what you are referring to is a Defect Detection Percentage metric and this one is defined as follow

[ QUOTE ]

DDP = Number of defects at the moment of software version release / Number of defects at the moment of software release + escaped defects found.

[/ QUOTE ]

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