Data Collection Statistical SQA
Total Serious Moderate Minor
Error No % No % No % N0 %
|
IES
|
205
|
22%
|
34
|
27%
|
68
|
18%
|
103
|
24%
|
|
MCC
|
156
|
17%
|
12
|
9%
|
68
|
18%
|
76
|
17%
|
|
IDS
|
48
|
5%
|
1
|
1%
|
24
|
6%
|
23
|
5%
|
|
VPS
|
25
|
3%
|
0
|
0%
|
15
|
4%
|
10
|
2%
|
|
EDR
|
130
|
14%
|
26
|
20%
|
68
|
18%
|
36
|
8%
|
|
IMI
|
58
|
6%
|
9
|
7%
|
18
|
5%
|
31
|
7%
|
|
EDL
|
45
|
5%
|
14
|
11%
|
12
|
3%
|
19
|
4%
|
|
IET
|
95
|
10%
|
12
|
9%
|
35
|
9%
|
48
|
11%
|
|
IID
|
36
|
4%
|
2
|
2%
|
20
|
5%
|
14
|
3%
|
|
PLT
|
60
|
6%
|
15
|
12%
|
19
|
5%
|
26
|
6%
|
|
HCI
|
28
|
3%
|
3
|
2%
|
17
|
4%
|
8
|
2%
|
|
MIS
|
56
|
6%
|
0
|
0%
|
15
|
4%
|
41
|
9%
|
|
Totals
|
942
|
100%
|
128
|
100%
|
379
|
100%
|
435
|
100%
|
Table - Data Collection for statistical SQA
Ws Wm, Wt =weighting factors for trivial errors and serious moderate where recommended values are Ws = 10, Wm =3, Wt = 1. The weighting factors for each phase should become bigger as development progresses. This rewards a company which finds errors early.
At the every step in the software engineering process, a phase index PI, is ∑computed. PIi = Ws (S/Ei) + Wt (T/Ei)
The error index (EI) is computed through calculating the cumulative effect or earn Pii weighting errors encountered later in the software engineering procedure more heavily than those encountered earlier.
EI = ∑ (I∗PI)/PS
=(PI1+2PI2 +3PIS3 +iPIi)PS
The error index can be used in conjunction with information collected which is illustrate in Table 10.2 to develop an overall indication of improvement in software quality.
The application of the statistical SQA and the pareto principle can be summarized in a single sentence. Spend your time focusing on things which are really matter but first be sure that you understand what really matters! Experienced organization practitioners agree that most actual hard defects can be traced to a relatively limited number of root causes. In the fact most practitioners have an intuitive feeling for the real causes of software defects but few have spent time collecting data to support their feelings. Through performing the basic steps of statistical SQA the vital few causes for defects can be appropriate and isolated corrections can be made.