55 Greene et al 2000 From this perspective data-mining refers to invalid statistical testing as a result of naive over-use of a sample. In particular,
{"Image DocumentName": "Greene et al 2000", "Image ImageDescription": "From this perspective data-mining refers to invalid statistical testing as a result of naive over-use of a sample. In particular, the use of a sample both for learning-inspiration and for testing of that which was learned or mined from the sample. Any test of a theory or model is corrupted if the test is conducted using data which overlaps that of any previous empirical study used to suggest that theory or model. The moral is clear. The claim that one specification is less data-mined than another is not sufficient to justify formal interpretation of regression statistics as in classical statistics. \u2026 In-sample tests\u2019 are useful as design criteria but only out-of-sample tests are precisely meaningful applications of statistics. Without out-of-sample testing there is no distinction between running regressions and constructing historical (ex post) narratives\u2026. But the most important fear of data-mining stems from legitimate doubts about the validity of most testing in over-worked time series data and from the false hope that if our own contribution to data-mining is small then our own research will somehow circumvent the problem of pre-test distortion of standard statistic distributions. But avoidance of explicit specification search will not cure our discomfort with sloppy in-sample tests\u2019 nor will it insulate us from dishonest or deluded results. Specification search is the only way to learn from the data. Out-of-sample testing of data-mined specifications is the only way to conduct statistically valid tests and create reliable knowledge. All else represents a wish for scientific validity unconstrained by scientific inputs, technology, method and sensibility.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}