After William Gosset (1876-1937), the 'Student' of Student's t, the best statisticians have distinguished economic (or agronomic or psychological or medical) significance from merely statistical 'significance' at conventional levels. A singular exception among the best was Ronald A. Fisher, who argued in the 1920s that statistical significance at the 0.05 level is a necessary and sufficient condition for establishing a scientific result. After Fisher many economists and some others - but rarely physicists, chemists, and geologists, who seldom use Fisher-significance - have mixed up the two kinds of significance. We have been writing on the matter for some decades, with other critics in medicine, sociology, psychology, and the like. Hoover and Siegler, despite a disdainful rhetoric, agree with the logic of our case. Fisherian 'significance,' they agree, is neither necessary nor sufficient for scientific significance. But they claim that economists already know this and that Fisherian tests can still be used for specification searches. Neither claim seems to be true. Our massive evidence that economists get it wrong appears to hold up. And if rhetorical standards are needed to decide the importance of a coefficient in the scientific conversation, so are they needed when searching for an equation to fit. Fisherian 'significance' signifies nearly nothing, and empirical economics as actually practiced is in crisis.
