Table 1.

Example of application of the LQAS method to detect the probability of 80% or 50% coverage of health-area residents with respect to vaccination according to various sample sizes and number of unimmunized children

Sample size (n)	No. in the sample unimmunized (d)	Probability of detecting health areas with 80% coverage as adequate (a)	Probability of detecting health areas with 50% coverage as inadequate (b)	Provider risk (1–a)	Consumer risk (1–b)	Total classification error (1–a)+(1–b)
8	0	0.17	1	0.83	0	0.83
	1	0.50	0.96	0.50	0.04	0.54
	2	0.79	0.83	0.21	0.17	0.38*
	3	0.94	0.64	0.06	0.36	0.42
12	0	0.07	1.00	0.93	0.00	0.93
	1	0.28	1.00	0.72	0.00	0.73
	2	0.56	0.98	0.44	0.02	0.48
	3	0.80	0.93	0.20	0.07	0.28
	4	0.93	0.81	0.07	0.19	0.27*
	5	0.98	0.61	0.02	0.39	0.41
14	0	0.04	1	0.96	0	0.96
	1	0.20	1	0.80	0	0.80
	2	0.45	0.99	0.55	0.01	0.56
	3	0.70	0.97	0.30	0.03	0.33
	4	0.87	0.91	0.13	0.09	0.22*
	5	0.96	0.79	0.04	0.21	0.25
19	0	0.01	1	0.99	0	0.99
	1	0.08	1	0.92	0	0.92
	2	0.24	1	0.76	0	0.76
	3	0.46	1	0.54	0	0.55
	4	0.67	0.99	0.33	0.01	0.34
	5	0.84	0.97	0.16	0.03	0.20
	6	0.93	0.92	0.07	0.08	0.15*
	7	0.98	0.82	0.02	0.18	0.20
28	5	0.50	1	0.50	0	0.50
	6	0.68	1	0.32	0	0.32
	7	0.81	0.99	0.19	0.01	0.20
	8	0.91	0.98	0.09	0.02	0.11
	9	0.96	0.96	0.04	0.04	0.08*
	10	0.99	0.90	0.01	0.10	0.11

*Optimal decision rule for a sample size;

LQAS=Lot quality assurance sampling

Source: Grant EL, Leavenworth RS. 1988:391–425 (7)