80:20 rules! - Building software smarter

http://www.youtube.com/watch?v=zXRxsRgLRZ4

- about 80% of the defects come from 20% of the modules and about half the moudle are defect free

- about of 90% downtown comes from at most 10% of the defects.

- once we find a defect, there is a strong clance we are in a sweet spot and will find more in the same place.

- if we are running tests in an area and not finding defets, there is a strong chance it may be defect free.(Not: chance not guarantee)

- Work on sweet spots for scripted and exploratory testing, or TDD or refactoring.

- A purpose of testing is to identify bug clusters

- A summary report has to inlude bug clusters information. This accumulated as a historical data.

ref)

Bad Smell

(http://blog.daum.net/volzh/12827818)

1. duplicated code

2. long method

3. long parameter list

4. switch and long if else statement

5. comments