Estimate the number of defects
Lincoln Index
The Lincoln Index relies on the assumption that testers have an equal chance of finding any bug
Assume that two testers have the probability of finding a bug with P1 and P2 respectively, and there are B total bugs in the application, then they may each find E1=P1 * B , E2=P2 * B defects
The probability that a particular defect is discovered at the same time is P1 * P2, therefore, it is expected that they can discover S= P1 * P2 * B defects at the same time, so the
total number of defects is B= E1 * E2/S
Example: In a project, Lisa found 8 defects, Ramon found 6 defects, and found 2 identical defects, so how many defects are there in total? A.
12
B. 24
C. 36 D.
14
Answer:
According to the above method, the total number of defects = 8 * 6/2 = 24, so choose B
Seibel Index
Seibel's formula: number of bugs = (E1+1)(E2+1)/(S+1)-1
Same as the previous example, use Seibel's formula to get the number of defects = (8+1) * (6+1 )/(2+1)-1=9*7/3-1=20 pieces