Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
If voters care about the size of the government's majority, then by-election votes should exaggerate national swings. Moreover, if there is uncertainty about the outcome of the general election and if voters' preferences are skewed in such a way as to give more weight to the 'downside' outcome (least favorite party wins) than the 'upside' (favored party wins with a larger than preferred majority), then there will be a systematic tendency for governments to lose by-elections, regardless of any changes in national support. These predictions go beyond those generated by conventional explanations. The theory is successfully tested against data from 383 postwar elections. Copyright 1998 by Kluwer Academic Publishers