Errors in Software

To describe the process suppose that a software development organization collects information on defects for a 1 year period. Some errors are uncovered as software is being established. Other defects are encountered after the software has been released to its end user although 100 of various errors are uncovered all can be tracked to one or more of the following causes:

1. Error in design logic (EDL)
2. Erroneous or Incomplete testing (IET)
3. Incomplete or Inaccurate documentation (IID)
4. Error in programming language translation of design (PLT)
5. Inconsistent or Ambiguous; human-computer interface (HCI)
6. Miscellaneous (MIS).
7. Incomplete or erroneous specification (IES)
8. Misinterpretation of customer communication (MCC)
9. Intentional deviation from specification (IDS)
10. Violation of programming standards (VPS)
11. Error in presenting data (EDR)
12. Inconsistent module interface (IMI)

For apply statistical SQA the Table 10.2 is develop the table indicates which MCC, IES and EDR are the vital few cause which account for 53 % of all errors.  It should be noted however that EDR, PLT, IES, and EDL would be selected as the vital few causes if only serious errors are considered. At one the vital case is determined; the software development companies can starts corrective action. Example for to correct MCC the software developer might implement facilitated application specification methods to improve the quality of customer specification and communication. To improve EDR the developer might obtain CASE tools for data modelling and perform more stringent data design reviews. The vital few causes are corrected.

In conjunction with the collection of defect data new candidates pop to the top of the stack through software developers can calculate an error index (EI) by each major step in the software engineering process [IEE94]. Later analysis and design and coding and testing and release the following data are gathered:

E_i =  the gross number of errors uncovered while during the ith step in the software engineering process

S_i   =the number of serious errors

M_i   =the number of moderate errors

T_i   =the number of minor errors

P_S  =Product size LOC design statements pages of documentation at the ith step