code: public double calculateMaximumAgreement() {
  		double A_O = calculateMaximumObservedAgreement();
  		double A_E = calculateExpectedAgreement();
  		if (A_E == 0.0)
  			return A_O;
  		else
  			return (A_O - A_E) / (1.0 - A_E);
  	}
docs: Computes the maximum possible value of the kappa coefficient for the
  provided study. In case of balanced off-marginals (i.e., an equal
  disagreement for each pair of categories), the maximum kappa is 1.
  In other cases, it decreases with a higher discrepancy of the
  distribution of disagreements.