. 2020 Mar 16;17(6):1946. doi: 10.3390/ijerph17061946

Table 2.

Measures of validity of commercially available data as compared to field audit data.

Field Audit Data					Validity Score
		Present	Absent	Sensitivity	$\frac{T P}{T P + F N}$
Commercially available data	Present	TP	FP	Specificity	$\frac{T N}{T N + F P}$
Commercially available data	Absent	FN	TN	PPV	$\frac{T P}{T P + F P}$
				Kappa	$\frac{p o - p e}{1 - p e}$
				Concordance	$\frac{T P}{T P + F P + F N}$

TP, true positive; FP, false positive; FN, false negative; TN, true negative; PPV, positive predictive value; p_o, observed agreement = $\frac{T P + T N}{T P + F P + F N + T N}$ ; p_e, expected agreement = $(\frac{T P + F P}{T P + F P + F N + T N} \times \frac{T P + F N}{T P + F P + F N + T N}) + (\frac{F N + T N}{T P + F P + F N + T N} \times \frac{F P + T N}{T P + F P + F N + T N})$ .