cindex                  package:gcl                  R Documentation

_C_o_m_p_u_t_e _t_h_e _c-_i_n_d_e_x

_D_e_s_c_r_i_p_t_i_o_n:

     The C-index is the probability of the classifier ranking a
     randomly chosen positive example as more positive than a randomly
     chosen negative example. It is related to the Wilcoxon rank sum
     statistic or Mann-Whitney U. It is equivalent to the area under
     the receiver operating curve.

_U_s_a_g_e:

     cindex(preds, acts)

_A_r_g_u_m_e_n_t_s:

   preds: A vector of predictions

    acts: A vector of the actual classes. Must be 0 or 1.

_V_a_l_u_e:

     The c-index.

_A_u_t_h_o_r(_s):

     Staal A. Vinterbo staal@dsg.harvard.edu

_R_e_f_e_r_e_n_c_e_s:

     J.A. Hanley and B.J. McNeil. The meaning and use of the area under
     a receiver operating characteristic (ROC) curve. Radiology,
     143:29-36, 1982.

_S_e_e _A_l_s_o:

     ~~objects to See Also as 'ci.eval'

_E_x_a_m_p_l_e_s:

     preds <- runif(10)
     acts <- round(runif(10))
     cindex(preds,acts)

