The curious attraction of Wagner's law

Wagner's 'law of increasing state activity' has recently been subjected to intensive use of recondite econometric testing procedures. An examination o f the relevant articles reveals ignorance both of Wagner's definition of 's tate activity' and of his insistence that he was not engaged in prediction. Consequently, the omission of public enterprises contained in Wagner's def inition leads to a model misspecification and the object of testing his hyp othesiss remains obscure.