Table 5. Unmatched outpatient visit data and final influenzalike illness (ILI) syndromic groupings*.

ICD-9 code	Unmatched data†					ILI group
	Total volume of code use (2001–04)	Average daily count	Correlation with positive specimens	p value	Signal -to-noise ratio	Original	New (final)
079.99	1,115,143	718	0.7746	<0.0001	2.84	Yes	Large
780.6	470,770	303	0.7545	<0.0001	2.55	Yes	Large
466.0	632,256	407	0.6693	<0.0001	2.17	Yes	Large
486	322,397	208	0.7180	<0.0001	2.09	Yes	Large
465.9	3,989,688	2,569	0.6758	<0.0001	1.91	Yes	Large
461.9	741,085	477	0.6017	<0.0001	1.81	No	Large
382.9	1,185,809	764	0.6286	<0.0001	1.76	No	Large
460	361,139	233	0.5552	<0.0001	1.55	Yes	Large
490	297,918	192	0.6337	<0.0001	1.50	Yes	Large
786.2	545,510	351	0.5573	<0.0001	1.24	Yes	Large
487.1	62,340	40	0.8696	<0.0001	5.59	Yes	Small
487.8	8,973	6	0.7926	<0.0001	4.74	Yes	Small
487.0	5,093	3	0.6205	<0.0001	3.11	Yes	Small
465.8	72,042	46	0.6384	<0.0001	1.86	Yes	Small
466.11	18,377	12	0.4800	<0.0001	1.83	Yes	–
466.19	68,127	44	0.5257	<0.0001	1.65	Yes	–
480.2	451	0	0.3316	<0.0001	1.64	Yes	–
462	1,436,325	925	0.5468	<0.0001	1.61	Yes	–
480.1	1,790	1	0.4083	<0.0001	1.58	Yes	–
382.00	277,270	179	0.4868	<0.0001	1.58	No	–
480.9	10,852	7	0.4562	<0.0001	1.44	Yes	–
478.9	7,434	5	0.4296	<0.0001	1.23	Yes	–
461.8	123,913	80	0.3083	<0.0001	1.14	No	–
465.0	33,760	22	0.4804	<0.0001	1.11	Yes	–
484.8	4,312	3	0.3202	<0.0001	1.11	Yes	–
480.8	11,708	8	0.3501	<0.0001	1.07	Yes	–
079.89	17,729	11	0.3355	<0.0001	1.05	Yes	–
485	7,954	5	0.4180	<0.0001	0.99	Yes	–
464.20	3,539	2	0.3852	<0.0001	0.88	Yes	–
463	168,499	108	0.3176	<0.0001	0.08	No	–
784.1	59,516	38	0.2994	<0.0001	0.59	Yes	–
464.10	1,736	1	0.2560	0.0002	0.56	Yes	–
480.0	287	0	0.0889	0.2082	0.24	Yes	–
464.00	22,470	14	0.1133	0.1085	0.14	Yes	–

*NOS, not otherwise specified; NEC, not elsewhere classified (as listed in the International Classification of Diseases, 9th Revision).
‡ Department of Defense–wide outpatient visit data, October 2000–December 2004.