jml                package:MiscPsycho                R Documentation

_J_o_i_n_t _M_a_x_i_m_u_m _L_i_k_e_l_i_h_o_o_d

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

     Estimates the Rasch model using joint maximum likelihood (JML)

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

     jml(dat, con = 0.001, bias = FALSE)

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

     dat: A data frame or matrix containing item responses

     con: Convergence criterion

    bias: Correction for JML bias

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

     JML estimation only has good asymptotic properties. Marginal
     Maximum Likelihood (MML) is a better technology for parameter
     estimation. However, this option is provided for users of Winsteps
     who may want to explore their data in R prior to working in
     Winsteps. JML is known to return biased parameter estimates. If
     bias = TRUE, then a correction for bias is made using (L-1)/L * b
     where L is the total number of test items and b is the original
     item parameter

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

     jml returns item parameter estimates, their asymptotic standard
     errors, the sample size per item, and the Infit and Outfit
     statistics found in Winsteps.

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

     Harold C. Doran

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

     Best Test Design. Wright and Stone (1979)

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

     ltm

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

