aidsConsist: Check Consistency of the AIDS
In micEconAids: Demand Analysis with the Almost Ideal Demand System (AIDS)

Description Usage Arguments Details Value Author(s) References See Also Examples

Check whether the specification of the AIDS is consistent with microeconomic demand theory (i.e. utility maximisation).

aidsConsist( priceNames, totExpName, coef, data,
   priceIndex = "TL", basePrices = NULL, baseShares = NULL,
   shareNames = NULL )

## S3 method for class 'aidsConsist'
print( x, ... )

## S3 method for class 'aidsEst'
checkConsist( object, observedShares = FALSE, ... )

`priceNames`	a vector of strings containing the names of the prices.
`totExpName`	a string containing the variable name of total expenditure.
`coef`	a list containing the coefficients alpha, beta, gamma, and (only for the translog price index) alpha0.
`data`	a data frame containing the data.
`priceIndex`	a character string specifying the price index (see `aidsPx`) or a numeric vector providing the log values of the price index (passed to `aidsMono`.
`basePrices`	a vector specifying the base prices for the Paasche, Laspeyres, and Tornqvist price index (passed to `aidsMono`.
`baseShares`	a vector specifying the base expenditure shares for the Laspeyres, simplified Laspeyres, and Tornqvist index (passed to `aidsMono`.
`shareNames`	a vector of strings containing the names of the expenditure shares (passed to `aidsConcav`.
`x`	an object of class `aidsConsist`.
`object`	an object of class `aidsEst`.
`observedShares`	logical. Using observed shares? (see details).
`...`	currently not used.

The checkConsist method for objects of class aidsEst extracts all relevant elements from an object returned by aidsEst and passes them as arguments to aidsConsist. The optional argument observedShares determines whether fitted (default) or observed expenditure shares are used in the price index of the LA-AIDS to check monotonicity and in the calculation of the subsitution matrix to check concavity.

aidsConsist and the checkConsist method return a list of class aidsConsist that contains following elements:

`addingUp`	logical. Is the addinp-up condition fulfilled?
`homogeneity`	logical. Is the homogeneity condition fulfilled?
`symmetry`	logical. Is the symmetry condition fulfilled?
`mono`	an object returned by `aidsMono`.
`concav`	an object returned by `aidsMono` (only if the symmetry condition is fulfilled and the translog price index is used, i.e. argument `priceIndex` is `"TL"`.

Arne Henningsen

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

Deaton, A.S. and J. Muellbauer (1980b) Economics and Consumer Behavior, Cambridge University Press, Cambridge.

aidsEst

   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" )

   estResult <- aidsEst( priceNames, shareNames, "xFood",
      data = Blanciforti86, method = "IL" )
   aidsConsist( priceNames, "xFood", data = Blanciforti86,
      coef = estResult$coef )

   # the same can be obtained in an easier way
   checkConsist( estResult )