cluster               package:survival               R Documentation

_I_d_e_n_t_i_f_y _C_l_u_s_t_e_r_s

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

     This is a special function used in the context of the Cox model. 
     It identifies correlated groups of observations, and is used on
     the right hand side of a formula.

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

     cluster(x)

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

       x: A character, factor, or numeric variable. 

_D_e_t_a_i_l_s:

     The function's only action is semantic, to mark a variable as the
     cluster indicator.

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

     'x'

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

     'coxph', 'Surv'

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

     ## Not run: 
     coxph(Surv(futime, fustat) ~ age + cluster(group), data = ovarian)
     ## End(Not run)

