Table 4

Mean percent of outbreak signals detected by six aberration detection algorithms, tested on seven outbreak durations, at an alert rate of 0.01

Duration:

C1

C2

C3

GLM

EWMA 0.4

EWMA 0.9

F value

p-value

1 day

Mean

59.8%

58.2%

44.5%

73.4%

52.6%

64.6%

2.58

0.03

Lower CI*

47.5%

45.7%

31.0%

62.4%

39.6%

52.4%

Upper CI

72.2%

70.7%

58.1%

84.4%

65.5%

76.8%

2 days

Mean

47.3%

49.1%

42.4%

64.2%

47.9%

55.2%

7.81

<0.0001

Lower CI

42.0%

43.7%

36.7%

59.2%

42.3%

49.8%

Upper CI

52.6%

54.4%

48.0%

69.2%

53.5%

60.7%

4 days

Mean

39.6%

43.5%

40.1%

57.7%

43.6%

48.9%

6.43

<0.0001

Lower CI

34.5%

38.2%

34.7%

52.6%

38.2%

43.5%

Upper CI

44.7%

48.8%

45.5%

62.7%

49.1%

54.4%

6 days

Mean

33.2%

39.8%

37.6%

54.0%

41.7%

45.5%

7.65

<0.0001

Lower CI

28.5%

34.7%

32.4%

48.9%

36.4%

40.2%

Upper CI

37.8%

44.9%

42.9%

59.0%

47.1%

50.8%

8 days

Mean

27.7%

36.4%

34.7%

51.3%

39.2%

42.2%

10.55

<0.0001

Lower CI

23.8%

31.7%

29.8%

46.3%

34.0%

37.2%

Upper CI

31.6%

41.2%

39.7%

56.2%

44.3%

47.3%

16 days

Mean

23.0%

31.0%

30.2%

47.7%

36.5%

38.3%

17.22

<0.0001

Lower CI

20.5%

27.4%

26.1%

43.2%

32.0%

33.9%

Upper CI

25.5%

34.6%

34.4%

52.2%

41.0%

42.7%

32 days

Mean

26.5%

31.2%

27.4%

47.5%

36.5%

37.5%

36.25

<0.0001

Lower CI

25.5%

29.7%

25.0%

44.2%

33.1%

34.6%

Upper CI

27.5%

32.8%

29.8%

50.8%

39.8%

40.3%

F value

35.81

38.67

31.48

64.53

37.68

46.16

p-value

<0.0001

<0.0001

<0.0001

<0.0001

<0.0001

<0.0001

* CI = 95% confidence interval

Jackson et al. BMC Medical Informatics and Decision Making 2007 7:6   doi:10.1186/1472-6947-7-6