Jurgen A. Doornik, David F. Hendry, and Felix Pretis Economics Department and Institute for New Economic Thinking at the Oxford Martin School, Oxford University, UK Department of Economics Discussion Paper Series Number 658 June 2013

Using an extenstion of general-to-specific modelling, based on the recent developments of impuse-indication saturation (ISS), we consider selecting significant step inidcators from a saturating set to capture location shifts. The approximate non-centrality of the test is derived for a variety of shifts using a 'split-half' analysis, the simplest specialization of a multiple-block search algorithm. Monte Carlo simulations confirm the accuracy of the nominal significance levels under the null, and show rejections when location shifts occur, improving in a non-null rejection frequency compared to the corresponding ISS-based and to Chow (1960) tests.