Table 4.

Summary of Hierarchical Regression Analyses: Percent of Post-Traumatic Stress Checklist, Civilian Version Variance Accounted for by Number of Blasts before and after Accounting for Demographics and Neurobehavioral Symptom Inventory Score

	Regression 1 Step 1: Blast			Regression 2 Step 1: Demographics Step 2: Blasts			Regression 3 Step 1: NSI Step 2: Demographics Step 3: Blasts
Predictor	R2	p	β	R2 (or Δ)	p (or Δ)	β	R2 (or Δ)	p (or Δ)	β
NSI							0.666	<0.001	0.797
Demographics				0.043	0.001		0.010	0.014
Blasts	0.010	0.017	1.012	0.023	<0.001	1.58	0.001	0.277	0.283

Demographics consisted of age, time since injury, duration of loss of consciousness and number of deployments. Demographic predictors were entered simultaneously in regressions two and three.

NSI, Neurobehavioral Symptom Inventory.