Table 5. Exemplary calculation of the alternative kappa statistic as proposed by Gwet (2002).

		Reviewer 1
		Acceptance	Rejection	Total
Reviewer 2	Acceptance	A	B	B1 = A+B
	Rejection	C	D	B2 = C+D
	Total	A1 = A+C	A2 = B+D	N

Alternative chance agreement probability:

e(y) = 2P₁(1-P₁).

Approximate chance that a rater (A or B) classifies a subject into category “acceptance”.

P₁ = [(A1+B1)/2]/N.

Alternative kappa statistic:

AC1 = [p-e(y)]/[1-e(y)].

Where p = (A+D)/N.