 Due to the difficulties of detecting neutrinos, it is much more difficult to determine the individual coefficients than in the equivalent matrix for the quarks (the CKM matrix).As noted above, PMNS matrix is unitary.That is, the sum of the squares of the values in each row and in each column, which represent the probabilities of different possible events given the same starting point, add up to 100%,

In the simplest case, the Standard Model posits three generations of neutrinos with Dirac mass that oscillate between three neutrino mass eigenvalues, an assumption that is made when best fit values for its parameters are calculated.