where po is the relative observed agreement among raters (identical to accuracy), and pe is the hypothetical probability of chance agreement, using the observed data to calculate the probabilities of each observer randomly seeing each category. If the raters are in complete agreement then κ = 1 {\textstyle \kappa =1} . If there is no agreement among the raters other than what would be expected by chance (as given by pe), κ = 0 {\textstyle \kappa =0} .