nwtco package:survival R Documentation _D_a_t_a _f_r_o_m _t_h_e _N_a_t_i_o_n_a_l _W_i_l_m'_s _T_u_m_o_r _S_t_u_d_y _D_e_s_c_r_i_p_t_i_o_n: Missing data/masurement error example. Tumor histology predicts survival, but prediction is stronger with central lab histology than with the local institution determination. _U_s_a_g_e: nwtco _F_o_r_m_a_t: A data frame with 4028 observations on the following 9 variables. '_s_e_q_n_o' id number '_i_n_s_t_i_t' Histology from local institution '_h_i_s_t_o_l' Histology from central lab '_s_t_a_g_e' Disease stage '_s_t_u_d_y' study '_r_e_l' indicator for relapse '_e_d_r_e_l' time to relapse '_a_g_e' age in months '_i_n._s_u_b_c_o_h_o_r_t' Included in the subcohort for the example in the paper _S_o_u_r_c_e: _R_e_f_e_r_e_n_c_e_s: NE Breslow and N Chatterjee (1999), Design and analysis of two-phase studies with binary outcome applied to Wilms tumour prognosis. _Applied Statistics_ *48*, 457-68. _E_x_a_m_p_l_e_s: with(nwtco, table(instit,histol)) anova(coxph(Surv(edrel,rel)~histol+instit,data=nwtco)) anova(coxph(Surv(edrel,rel)~instit+histol,data=nwtco))