“…This conclusion, of course, depends on the acceptability of the indicators used to measure B and P. In the studies by Barzel and Silberberg (1973), and Tollison et al (1975), for example, the use of "proportion of the population registered" as a measure of intensity of feeling about the election is open to question; it may be better to regard "willingness to register" as simply another indicator of "willingness to participate" rather than as an independent determinant of the voting decision. The "closeness" indicators can also be questioned, on the grounds that uncertainty of outcome is likely to increase the entertainment value of the election, hence to operate through D rather than P. This is, indeed, the interpretation given to the closeness indicator in Silver's (1973) study, and further support for this interpretation comes from the fact that in the three studies, where "interest in the campaign" is included as an independent variable in a regression analysis, closeness becomes insignificant (Silver, 1973;Ashenfelter and Kelley, 1975;Abramson and Aldrich, 1982) [6]. Yet it would probably be going too far to write off the "P-factor" completely, since, to the extent that B affects turn-out at all, it does so only if people believe that P, and hence BP, is significantly different from zero.…”