aidsBestA0              package:micEcon              R Documentation

_F_i_n_d '_b_e_s_t' _V_a_l_u_e _f_o_r _C_o_e_f_f_i_c_i_e_n_t _a_l_p_h_a _0

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

     Search for the intercept of the translog price index (alpha_0)
     that gives the best fit to the model, i.e. the value that leads to
     the smallest determinant of the residual covariance matrix (see
     Michalek and Keyzer, 1992).

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

        aidsBestA0( pNames, wNames, xtName,
           data = NULL, ivNames = NULL, method = "MK:L",
           a0min = -50, a0max = 50, stoprange = 3, stopiter = 10,
           verbose = FALSE, ... )

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

  pNames: a vector of strings containing the names of prices.

  wNames: a vector of strings containing the names of expenditure
          shares.

  xtName: a name of the total expenditure variable.

    data: a data frame containing the data.

 ivNames: a vector of strings containing the names of instrumental
          variables.

  method: the method to estimate the aids (see 'aidsEst').

   a0min: lower limit of the range for searching for alpha_0.

   a0max: upper limit of the range for searching for alpha_0.

stoprange: stop searching when the search interval is smaller than or
          equal to 'stoprange'.

stopiter: maximal number of iterations.

 verbose: print each determinant of the residual covariance matrix
          immediately after its calculation.

     ...: argunents passed to 'aidsEst'.

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

     Since the call of 'aidsEst' takes some time, the search algorithm
     is constructed to minimize the calls of the function 'aidsEst'.

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

     a list containing following objects: 

  alpha0: alpha_0 that gives the best fit.

allValues: all alpha_0 tested and the corresponding determinants of the
          residual covariance matrix.

    iter: number of iterations.

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

     Arne Henningsen ahenningsen@agric-econ.uni-kiel.de

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

     Deaton, A.S. and J. Muellbauer (1980) An Almost Ideal Demand
     System. _American Economic Review_, 70, p. 312-326.

     Michalek, J. and M. A. Keyzer (1992) Estimation of a two-stage
     LES-AIDS consumer demand system for eight EC countries. _European
     Review of Agricultural Economics_, 19 (2), p. 137-163.

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

     'aidsEst'

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

        data( Blanciforti86 )
        bestA0 <- aidsBestA0( c( "pFood1", "pFood2", "pFood3", "pFood4" ),
           c( "wFood1", "wFood2", "wFood3", "wFood4" ), "xFood",
           data = Blanciforti86, method = "MK:L" ) # may take some time
        bestA0$alpha0
        plot( bestA0$allValues ) # this should be convex

