Check validity of Lorenz Quadratic fit
Source:R/gd_compute_pip_stats_lq.R
check_curve_validity_lq.Rdcheck_curve_validity_lq() checks the validity of the Lorenz Quadratic fit
Arguments
- A
numeric: Lorenz curve coefficient. Output of
regres_lq()$coef[1].- B
numeric: Lorenz curve coefficient. Output of
regres_lq()$coef[2].- C
numeric: Lorenz curve coefficient. Output of
regres_lq()$coef[3].- key_values
named list: key values for lq fit, calculated using A, B, C parameters using gd_lq_key_values
Details
e numeric: e = -(A + B + C + 1): condition for the curve to go through (1, 1).
m numeric: m = (B^2) - (4 * A). m < 0: condition for the curve to be an ellipse (m is called alpha in paper).
n numeric: n = (2 * B * e) - (4 * C). n is called Beta in paper r r = (n^2) - (4 * m * e^2). r is called K in paper.
References
Datt, G. 1998. "Computational Tools For Poverty Measurement And Analysis". FCND Discussion Paper 50. World Bank, Washington, DC.
Krause, M. 2013. "Corrigendum to Elliptical Lorenz curves". Journal of Econometrics 174 (1): 44.
Villasenor, J., B. C. Arnold. 1989. "Elliptical Lorenz curves". Journal of Econometrics 40 (2): 327-338.