Interpreting kappa values
Kappa values range from -1 to +1. The higher the value of kappa, the stronger the agreement.
When:Kappa = 1, perfect agreement exists.Kappa = 0, agreement is the same as would be expected by chance.Kappa < 0, agreement is weaker than expected by chance; this rarely occurs.
Usually a kappa value of at least 0.70 is required, but kappa values close to 0.90 are preferred.
When you have ordinal ratings, such as defect severity ratings on a scale of 1-5, Kendall's coefficients, which take ordering into consideration, are usually more appropriate statistics to determine association than kappa alone.