Statistics Meeting Book (May 15, 2019)

A = number of pairs with positive results by both methods B = number of pairs with positive result by candidate and negative result by reference C = number of pairs with negative result by candidate and positive result by reference D = number of pairs with negative results by both methods N = A+B+C+D

Then:

POD(c) = (A+B)/N POD(r) = (A+C)/N dPOD = (B-C)/N

Report POD(c), POD(r) and dPOD for all levels tested.

Confidence Interval of the dPOD estimate:

For each level tested, calculate the standard error of the dPOD estimate:

§ ¨ ¨ ©

· ¸ ¸ ¹

2

2 B C B C N N § ¨ © 2 2

· ¸ ¹

( SE dPOD )

N

And the 95% confidence interval of the dPOD estimate is: 1.96 ( ) dPOD SE dPOD r u

ANNEX D Summary Data Table for Qualitative Method Single Laboratory Studies

Table D1. Comparative results for the detection of Listeria innocua in raw shrimp

Concentration

Candidate presumptive (CP)

Candidate confirmed (CC)

Candidate method (C)

Reference method (R)

C vs R

CP vs CC

Statistic

MPN/25 g

N

x

POD(CP)

N

x

POD(CC)

N

x

POD(C)

N

x

POD(R)

dPOD(C,R)

dPOD(CP,CC)

Estimate

0.00

20

0

0.00

20

0

0.00

20

0

0.00

20

0

0.00

0.00

0.00

LCL

0.00

0.00

0.00

0.00

0.00

–0.16

–0.16

UCL

1.50

0.16

0.16

0.16

0.16

0.16

0.16

Estimate

0.80

20

12

0.60

20

10

0.50

20

10

0.50

20

11

0.55

–0.05

0.10

LCL

0.43

0.39

0.30

0.30

0.34

–0.33

–0.19

UCL

1.39

0.78

0.70

0.70

0.74

0.24

0.37

Estimate

3.00

20

20

1.00

20

20

1.00

20

20

1.00

20

19

0.95

0.05

0.00

LCL

1.58

0.84

0.84

0.84

0.76

–0.12

–0.16

UCL

5.68

1.00

1.00

1.00

1.00

0.24

0.16

Estimate

17.00

20

20

1.00

20

20

1.00

20

20

1.00

20

20

1.00

0.00

0.00

LCL

0.27

0.84

0.84

0.84

0.84

–0.16

–0.16

UCL

1060

1.00

1.00

1.00

1.00

0.16

0.16