lmtest (version 0.9-38)

ChickEgg: Chickens, Eggs, and Causality

Description

US chicken population and egg production.

Usage

data(ChickEgg)

Format

An annual time series from 1930 to 1983 with 2 variables.

chicken

number of chickens (December 1 population of all US chickens excluding commercial broilers),

egg

number of eggs (US egg production in millions of dozens).

References

Thurman W.N. & Fisher M.E. (1988), Chickens, Eggs, and Causality, or Which Came First?, American Journal of Agricultural Economics, 237-238.

Examples

# NOT RUN {
## Which came first: the chicken or the egg?
data(ChickEgg)
## chickens granger-cause eggs?
grangertest(egg ~ chicken, order = 3, data = ChickEgg)
## eggs granger-cause chickens?
grangertest(chicken ~ egg, order = 3, data = ChickEgg)

## To perform the same tests `by hand', you can use dynlm() and waldtest():
if(require(dynlm)) {
  ## chickens granger-cause eggs?
  em <- dynlm(egg ~ L(egg, 1) + L(egg, 2) + L(egg, 3), data = ChickEgg)
  em2 <- update(em, . ~ . + L(chicken, 1) + L(chicken, 2) + L(chicken, 3))
  waldtest(em, em2)

  ## eggs granger-cause chickens?
  cm <- dynlm(chicken ~ L(chicken, 1) + L(chicken, 2) + L(chicken, 3), data = ChickEgg)
  cm2 <- update(cm, . ~ . + L(egg, 1) + L(egg, 2) + L(egg, 3))
  waldtest(cm, cm2)
}
# }