IN THIS election, the percentage of spoilt votes was lowest in the five constituencies where opposition parties fared best: Hougang, Aljunied GRC, Potong Pasir, Joo Chiat and East Coast GRC.
Hougang is at the bottom of the heap, with just 1.13 per cent of voters spoiling their votes. Aljunied GRC came in second with 1.34 per cent. The national share of spoilt votes was 2.17 per cent.
Political observers who crunched the constituency-level data for spoilt votes say there is a clear trend.
There were fewer spoilt votes in closely contested wards, or where the opposition was more viable, because the voter perceived that his or her vote was more likely to make a difference.
Analysts point to the other end of the spectrum in making the point.
The percentage of spoilt votes was highest in Ang Mo Kio GRC (3.01 per cent) and Pasir Ris-Punggol GRC (2.85 per cent), where Prime Minister Lee Hsien Loong and Deputy Prime Minister Teo Chee Hean led teams against relatively weak opposition slates.
Said political scientist Derek da Cunha: 'This shows that Singapore has a pretty sophisticated and rational electorate. They have a good sense of whether or not a constituency is going to be keenly fought, even without polling data.'
Agreeing, Associate Professor Tan Ern Ser of the National University of Singapore said the five electoral districts with low spoilt vote proportions were those in which the battle lines were most 'clearly drawn'.
Which party is contesting matters too. Of the 10 constituencies with the lowest share of spoilt votes, seven were contested by the Workers' Party (WP).
Former Nominated MP Zulkifli Baharudin said this showed that some voters were frustrated with the People's Action Party (PAP), but did not simply vote for any opposition party.
If the WP was the party challenging the PAP, they were willing to vote for the opposition. But if no compelling candidate came to town, they would rather spoil their votes in protest.
'The WP was the most effective in translating voter frustration into votes,' said Mr Zulkifli.
Voter turnout also varied significantly from one constituency to the next, although the trend is less clear.
Turnout was lowest in Joo Chiat (87.0 per cent) and highest in Sengkang West (95.6 per cent).
Political observer Azhar Ghani noted that the voter turnout appeared to be lower in areas with a lot of private housing (Holland-Bukit Timah GRC, Joo Chiat and Mountbatten), or where the proportion of older residents was higher (Radin Mas, Moulmein-Kallang GRC).
'For the older folk, the message to vote might not have reached some of them. Even if it did, some might not be too interested, or have difficulties getting to the voting stations,' he said.
Mr Long Foo Choo, the honorary chairman of the citizens' consultative committee in Joo Chiat, said the higher proportion of affluent households means more may have been overseas on holiday during the vote.
Because of its proximity to Changi Airport, Joo Chiat is also home to many who work in the globe-trotting airline industry, some of whom would have been among the 2,877 who failed to vote, he added.
Nationwide, some 153,000 voters on the rolls, or 6.9 per cent, did not show up, even though voting is compulsory.
Constituencies with least spoilt votes
Aljunied GRC: 1.34%
Potong Pasir: 1.51%
Joo Chiat: 1.64%
East Coast GRC: 1.66%
Constituencies with lowest voter turnouts
Joo Chiat: 86.96%
Moulmein-Kallang GRC: 89.28%
Holland-Bukit Timah GRC: 90.3%
Bishan-Toa Payoh GRC: 90.99%