Table Table 1.

A 2 × 2 table constructed from data reported by da Silva et al. 55 on the association between allelic variants of rs1800544 in ADRA2 and clinical response to methylphenidate in ADHD, primarily inattentive type ( P  = 0.016), from which the corresponding values for sensitivity, specificity, PPV, and NPV have been calculated

	Improvement	No improvement
ADRA2 rs1800544 G allele present (G/G or G/C)	29	11	40
ADRA2 rs1800544 G allele absent (C/C)	9	10	19
	38	21	59

ADHD, attention‐deficit/hyperactivity disorder; ADRA2, adrenergic α2A receptor gene; NPV, negative predictive value; PPV, positive predictive value.

Sensitivity: 29/38 = 76.3%.

Specificity: 10/21 = 47.6%.

PPV: 29/40 = 72.5%.

NPV: 10/19 = 52.6%.