Table 5.

 Caseness at baseline as a predictor of caseness at follow-up in Telic cohorts (n=669): likelihood ratios, sensitivity, specificity, and positive and negative predictive values (with 95% confidence intervals)

	Positive likelihood ratio	Negative likelihood ratio	Sensitivity	Specificity	Positive predictive value	Negative predictive value
Full and abridged questionnaires (using questions common to both):
GHQ	2.6 (1.9 to 3.7)	0.76 (0.66 to 0.87)	0.34 (0.25 to 0.43)	0.87 (0.84 to 0.90)	0.36 (0.27 to 0.46)	0.86 (0.83 to 0.89)
PTSD	3.9 (0.5 to 28.0)	0.95 (0.82 to 1.09)	0.07 (0.00 to 0.34)	0.98 (0.97 to 0.99)	0.08 (0.00 to 0.36)	0.98 (0.97 to 0.99)
Symptoms	4.7 (3.2 to 7.0)	0.72 (0.65 to 0.80)	0.33 (0.27 to 0.41)	0.93 (0.90 to 0.95)	0.65 (0.54 to 0.74)	0.78 (0.75 to 0.82)
Self perception of health	6.5 (4.3 to 9.8)	0.63 (0.53 to 0.76)	0.41 (0.30 to 0.52)	0.94 (0.91 to 0.96)	0.47 (0.35 to 0.59)	0.92 (0.90 to 0.94)
Full questionnaire:
GHQ	3.2 (1.9 to 5.3)	0.74 (0.62 to 0.90)	0.33 (0.21 to 0.47)	0.90 (0.85 to 0.93)	0.40 (0.26 to 0.56)	0.86 (0.82 to 0.90)
PTSD	13.3 (3.2 to 56.0)	0.76 (0.51 to 1.14)	0.25 (0.03 to 0.65)	0.98 (0.96 to 0.99)	0.25 (0.03 to 0.65)	0.98 (0.96 to 0.99)
Symptoms	3.5 (2.5 to 5.0)	0.52 (0.41 to 0.65)	0.57 (0.46 to 0.67)	0.84 (0.79 to 0.88)	0.60 (0.49 to 0.70)	0.82 (0.77 to 0.87)
Alcohol	2.9 (1.7 to 5.0)	0.80 (0.68 to 0.93)	0.28 (0.17 to 0.40)	0.90 (0.86 to 0.94)	0.42 (0.27 to 0.58)	0.83 (0.79 to 0.88)

GHQ=general health questionnaire; PTSD=post-traumatic stress disorder.