 Many important generalizations in economics are causal claims. For example, the law of demand asserts that a price increase will (ceteris paribus) diminish the quantity demanded. (It does not merely assert an inverse relationship between price and demand. When demand increases for some other reason, such as a change in tastes, price increases.) Econometricians have also been deeply concerned with the possibilities of determining causal relations from statistical evidence and with the relevance of causal relations to the possibility of consistent estimation of parameter values. Since concerns about the consequences of alternative policies are so central to economics, causal inquiry is unavoidable.