Election Database ( http://election.polarbears.com )
Home
Screenshots
Download
Tips
Help
Articles
History
Future
New
Contact
Links
Online

















Effective First Preference Vote

In the NI Assembly election in 1998, the UUP won the highest number of seats (28 out of 110) despite obtaining fewer first preferences than the SDLP, who won only 24. Given that the constituencies were fairly drawn (there were no complaints from any of the parties), there are two possible reasons for this:-
a) the UUP was better at attracting transfers
b) there was a lower turnout in the constituencies where the UUP support was highest

As a means of calculating how successful the UUP was at attracting transfers, I calculated the Maximum Preference Vote (MPV). This is calculated by taking the party vote in each constituency at whichever count it is highest. This did not provide the answer - the SDLP's MPV was still higher than that of the UUP.

The second possibility can be examined by calculating the Effective First Preference Vote (EFPV). This is calculated by adjusting first preference vote (FPV) so that the votes cast in each constituency are adjusted so that they are relative to the size of the constituency. This did produce a significant result - with the UUP vote increasing by 0.27% and the SDLP vote decreasing by 0.90%. The following table shows the results:-
PartyEFPVFPVEFPV - FPVMPVSeats
uup 21.5221.250.2724.8028
sdl 21.0621.96-0.9025.4224
dup 18.2318.140.0919.9820
sf 16.9617.63-0.6718.8018
all 7.006.500.507.756
uku 4.76 4.510.255.645
pup 2.822.550.273.092
otu* 2.732.680.053.593
wom 1.641.610.032.442
ind 1.131.110.021.190
udp 1.12 1.07 0.051.270
lab 0.34 0.34 0.000.380
wp 0.250.25 0.000.270
con 0.25 0.23 0.020.240
nlp 0.10 0.10 0.000.110
gp 0.09 0.09 0.000.100
Note: otu=other unionists

The results certainly account for the UUP winning more seats than the SDLP. Perhaps they also indicate that nationalists are more likely to vote than unionists, and that the more moderate a unionist is, the less likely they are to vote.
© Ciaran Quinn, Dublin - last updated on 24th June 2000