aidsCalc: Shares and Quantities of the Almost Ideal Demand System

Description

Given prices, total expenditure and coefficients this function calculates the demanded quantities and expenditure shares based on the Almost Ideal Demand System.

Usage

aidsCalc( priceNames, totExpName, data = NULL, px = "TL", lnp = NULL,
      coef = NULL, alpha0 = ifelse( is.null( coef$alpha0 ), 0,
      coef$alpha0 ) )

Arguments

priceNames

a vector of strings containing the names of the prices.

totExpName

a string containing the variable name of total expenditure.

data

a data frame containing the data.

prices index (see aidsPx).

lnp

log of the price index (only required if 'px' is not 'TL').

coef

a list containing the coefficients alpha, beta and gamma.

alpha0

coefficient $\alpha_0$ of the translog price index.

Value

aidsCalc returns a list with following elements:
sharesa data frame containing the calculated expenditure shares.
quantitiesa data frame containing the calculated quantites.

References

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

Examples

Run this code

data( Blanciforti86 )
   # Data on food consumption are available only for the first 32 years
   Blanciforti86 <- Blanciforti86[ 1:32, ]

   priceNames <- c( "pFood1", "pFood2", "pFood3", "pFood4" )
   shareNames <- c( "wFood1", "wFood2", "wFood3", "wFood4" )

   ## LA-AIDS
   estResult <- aidsEst( priceNames, shareNames, "xFood",
      data = Blanciforti86, method = "LA:L" )

   lnp <- aidsPx( "L", priceNames, shareNames, Blanciforti86 )

   fitted <- aidsCalc( priceNames, "xFood", Blanciforti86,
      coef = estResult$coef, lnp = lnp )

   fitted$shares  # equal to estResult$wFitted
   fitted$quant   # equal to estResult$qFitted

   ## AIDS
   estResult <- aidsEst( priceNames, shareNames, "xFood",
      data = Blanciforti86, method = "IL:L" )

   fitted <- aidsCalc( priceNames, "xFood", Blanciforti86,
      coef = estResult$coef )

   fitted$shares  # equal to estResult$wFitted
   fitted$quant   # equal to estResult$qFitted

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