. 2017 Jun 13;3(2):e35. doi: 10.2196/publichealth.5939

Table 4.

Classification evaluation using a random sample of 200 tweets (100 containing the keyword “stress” and 100 containing the keyword “relax”) from New York in dataset 2.

Classification	SVM (linear kernel)
Classification	Acc^a (%)	Sen^b (%)	Spec^c (%)	PPV^d (%)
Stress vs nonstress	75.0	76.7	70.4	87.5
Relaxation vs nonrelaxation	66.0	67.4	57.1	90.6
First-hand vs nonfirst-hand experience stress	68.0	44.0	92.0	84.6
First-hand vs nonfirst-hand experience relaxation	92.0	87.5	100.0	100.0

^aAcc: accuracy.

^bSen: sensitivity.

^cSpec: specificity.

^dPPV: positive predictive value.