Table 3

Optimised moving average charts

Approach solution		Disjunctive (or) combinations			Optimal individual MA chart
Approach solution		Optimal MA combination	Each MA chart individually		Optimal individual MA chart
Parameters	Baseline data	N/A	Network	Local	Network
	Baseline size	N/A	18 (3–24)	3 (3)	12 (3–24)
	Baseline lag	N/A	6 (0–24)	3 (3–24)	3 (0–12)
	MA span	N/A	12 (12)	6 (6–12)	12 (12)
	CL width (σ)	N/A	1 (1)	1 (1–2)	1 (1)
Chart performance	Sensitivity	0.90 (0.88)	0.72 (0.74)	0.53 (0.45)	0.73 (0.71)
	Specificity	0.67 (0.75)	0.79 (0.86)	0.84 (0.86)	0.77 (0.86)
	PPV	0.56(0.65)	0.62 (0.73)	0.61 (0.63)	0.60 (0.72)
	NPV	0.94 (0.92)	0.86 (0.87)	0.79 (0.75)	0.86 (0.85)
	Positive LLR	2.73 (3.55)	3.45 (5.28)	3.34 (3.25)	3.23 (4.94)
	Negative LLR	0.15 (0.16)	0.36 (0.30)	0.56 (0.64)	0.35 (0.34)
	Youden’s index	0.57 (0.63)	0.51 (0.60)	0.37 (0.31)	0.50 (0.57)
	Markedness	0.50 (0.57)	0.47 (0.60)	0.40 (0.38)	0.46 (0.57)
	Diagnostic OR	18.8 (22.3)	9.70 (17.6)	5.97 (5.07)	9.20 (14.6)
	Accuracy	0.74 (0.80)	0.77 (0.82)	0.74 (0.72)	0.76 (0.81)
	F₁ score	0.69 (0.75)	0.66 (0.74)	0.54 (0.52)	0.66 (0.72)
	Signals/month	0.24 (0.21)	0.19 (0.17)	0.08 (0.08)	0.20 (0.18)
	Rank	7 (661) of 6 478 200	11 (1) of 3600	367 (748) of 3600	18 (36) of 3600

Chart parameters and performance for the optimal dual-chart approach, each of these two charts individually, and optimal individual charts (overall and relying on local data only). Parameter values are listed as median and, in parentheses, range over the best 20 solutions in each category. Performance measures and ranks (out of 3600 individual and 32.4 million dual charts) are based on the training dataset, with values in parentheses based on the validation dataset.
σ, estimated SD; CL, control limit; LLR, log likelihood ratio; MA, moving average;N/A, not applicable; NPV, negative predictive value; PPV, positive predictive value.