Table 4.

2x2 contingency tables comparing the test characteristics of the PediBIRN network’s 3- and 4-variable clinical decision rules.

Applying the PediBIRN-4 and AHT Definitional Criteria			Applying the PediBIRN-3 and AHT Definitional Criteria			p values
	AHT	Other		AHT	Other
Higher Risk	409	343	Higher Risk	399	242
Lower risk	19	202	Lower risk	29	303
	Value	(95% CI)		Value	(95% CI)
Sensitivity	.96	(.94-.98)	Sensitivity	.93	(.91-.96)	.002
Specificity	.37	(.33-.41)	Specificity	.56	(.51-.60)	<.001
PPV	.54	(.51-.58)	PPV	.62	(.58-.66)	<.001
NPV	.91	(.88-.95)	NPV	.91	(.88-.94)	.901
(+) LR	1.52	(1.42-1.62)	(+) LR	2.10	(1.90-2.31)	<.001
(−) LR	.12	(.08-.19)	(−) LR	.12	(.09-.17)	.902
ROC AUC	.77	(.74-.80)	ROC AUC	.83	(.80-.85)	.002
Applying the PediBIRN-4 and Physicians’ Final Diagnoses			Applying the PediBIRN-3 and Physicians’ Final Diagnoses			p values
	AHT	Other		AHT	Other
Higher Risk	484	268	Higher Risk	472	169
Lower risk	12	209	Lower risk	24	308
	Value	(95% CI)		Value	(95% CI)
Sensitivity	.98	(.96-.99)	Sensitivity	.95	(.93-.97)	.001
Specificity	.44	(.39-.48)	Specificity	.65	(.60-.69)	<.001
PPV	.64	(.61-.68)	PPV	.74	(.70-.77)	<.001
NPV	.95	(.92-.98)	NPV	.93	(.90-.96)	.107
(+) LR	1.74	(1.60-1.88)	(+) LR	2.69	(2.38-3.04)	<.001
(−) LR	.06	(.03-.10)	(−) LR	.07	(.05-.11)	.142
ROC AUC	.82	(.80-.85)	ROC AUC	.89	(.87-.91)	<.001

Abbreviations: AHT=abusive head trauma, CI=confidence interval, PediBIRN=pediatric brain injury research network; LR=likelihood ratio, NPV=negative predictive value, PPV=positive predictive value, ROC AUC=area under the receiver operating characteristics curve