DublinCity Council’sRosie Hackett Bridge:A Landmark in Decision-Making
On 2 September, 2013, DublinCityCouncil votedtoname the newestbridge overthe RiverLiffeythe
Rosie HackettBridge.Whatmakesthisa landmarkdecisionisthatitseemstohave beenthe first
authoritative decisiontakenbyapublicbodyinIreland – and perhapseveninEurope – to have used
the votingprocedure knownasthe Borda Count,referredtointhe Council’sproceedingsasa
Preferendum (DublinCityCouncil2013a, item24). Thisreport summarisesthe process, analysesthe
results,anddiscussessome of the technical issuesthatarise withthismethodof voting.Itconcludes
that the procedure waswell suitedtothe taskinhand.
The processfor namingthe bridge wasreferredtothe CommemorativeNamingCommittee chaired
by CouncillorDermotLacey.AccordingtoLacey (personal communication),the committee agreed
fromthe start that itwoulduse an open,participatoryprocesstofindaname,andinvited
submissionsfromthe public.Inthe course of the process,itreceived thousandsof itemsof
correspondence,andofficial applicationsfor85 names.This initial listwasnarroweddowntoabout
thirtythrougha consensual process withinthe committee, startingby eliminatingnamesof people
whowere still alive orhaddiedlessthantwentyyearsearlier,aswell asfigureswhohadalready
beenhonoured byapublicnaming.The resultinglistwasthenfurtherreducedbydiscussionwithin
the committee,leadinginstagestoa listof seventeenandthen ten(DublinCityCouncil 2013b).
The listof tenwas reducedwithinthe committee toashortlistof five,usingaversionof aBorda
Countvote among the six membersinattendance.The finalshortlistwasputto the full council,
where all fifty-one membersparticipatedinaBorda Countvote. Detailsof these votes are given
The Borda Count
The Borda Count (hereafterBC) isa methodof votingnamedafterthe eighteenth-century French
mathematician whodevelopedit,Jean-Charlesde Borda.Itis designedtopickawinner (orsetof
winners) fromagroupof more than twooptionsor candidates.The basicBCmethodoperatesas
follows:Eachvoterindicatestheir opiniononthe options by numberingthem1,2, 3… inorder of
preference.If there are n options, avoter’sfirstpreference isgiven n points,theirsecondpreference
n-1,and so on.All of the pointsare addedup andthe optionwiththe highesttotal isthe winner.
The main advantage of the BC is thatit takesintoaccount voters’preferences amongthe complete
setof options,andtherefore favourspoliciesthathave wide support.Bycontrast,majorityrule only
considersfirstpreferences,and canthereby leadtodecisionsthatare stronglyopposedbyalarge
minorityof the electorate.
1 Emeritus Professor,School of Social Justice,University CollegeDublin.I am grateful to Councillor Dermot
Lacey and to Paula Ebbs in the Dublin City Council Secretariatfor their assistance,and to Peter Emerson and
Phil Kearney for their comments and suggestions.
There are several variantsof the basicBC method.Forinstance, the best-known example in Europe
of BC votingisthe EurovisionSongContest,whereeachcountryvotes for their top ten alternatives,
and the top two of these are given 12 and 10 points instead of 10 and 9.
One of the mostcommon questionsabout the BChas to do withincompleteballots.If, inafive-
optioncontext,avoteronlyindicatestheirfirstpreference andthisvote isgiven5points, itgainsa
5-pointleadoverall the otheralternatives,whichseemsunfair.Inthe ModifiedBCsystem (MBC),
developedbyEmerson (Emerson2012),the solutionistogive a voter’stoppreference mpoints,
where mis the numberof options actually votedfor. Soif a voterhas indicated only theirfirsttwo
preferences,these are given2pointsand1 point. The discussionbelow displays bothBCandMBC
Use of the Borda Count by the Commemorative Naming Committee
The committee usedaformof BC to reduce the shortlistfromtento five. Eachmemberindicated
theirtopfive preferences onasecretballot.All six votersusedall fiveof theirpreferences.Inthe
count,5 pointswasgiventoa firstpreference,4to a second,etc. The five optionswiththe highest
scoreswere includedinthe final shortlist (DublinCityCouncil 2013b).Table 1 showsthe complete
count andits result.
Table 1. Committee vote. Numbers above the line are preferences. Selected shortlist in red.
In Ireland,the question naturally arises of how the BC compares with Proportional Representation
by Single Transferable Vote (PRSTV). This ballot shows a very clear difference. Since exactly five of
the options received someone’s first preference, those five would have been chosen by PRSTV.2
Theyinclude AbbeyandSigerson insteadof Duff andStoker.Proponents of the BC argue that such a
result neglects the clear evidence that Duff is much more popular with the electorate as a whole
than eitherAbbeyorSigerson.Sincethe pointof thisdecisionis to reflect public opinion as a whole
rather than to select public representatives, it makes more sense to use a procedure that reflects
overall popularity than one, like PRSTV, that privileges first preferences. (The first-past-the-post
result in this case would have been the same as PRSTV, with the same disadvantage.)
The use of the Borda Count in full Council
2 The standard full method here would startby treating each vote as 100,setting the quota at101, and
identifyingHackett’s surplus as 99.Sincethis is less than the 100 votes polled by four other options,those
options would be deemed selected.
voter Abbey Bermingh Connolly Duff Hackett Mills Sigerson Stoker Walton Yeats
1 3 5 1 4 2
2 5 1 3 4 2
3 2 4 3 1 5
4 2 4 5 1 3
5 1 3 2 5 4
6 2 3 1 4 5
BC score 6 19 4 15 14 10 7 8 3 4
rank 7 1 8= 2 3 4 6 5 10 8=
1st prefs 1 1 0 0 2 1 1 0 0 0
In the full Council meeting,all 51councillorswere invitedtoindicate theirpreferencesamongthe
five shortlistedalternatives.Atthe meeting,the chair(LordMayor OisinQuinn) wasaskedif itwas
necessaryto rank all five alternatives.He repliedthat voterswere notrequiredtodoso,but that
theywouldbe answerable totheirconstituentsforwhateverwaytheyhadcompletedtheirballots,
as these wouldbe made public. Onlytwelvecouncillorsreturnedincomplete ballots. ‘Rosie Hackett’
wonthe vote with192 points.Table 3 givesthe result of the ballot(‘BCscore’) andalsoshowswhat
the resultwouldhave beenusingthe ModifiedBordaCount(‘MBCscore’). Inthiscase,the use of
MBC wouldnothave affectedthe winner,butitwouldhave ledtoa tie forsecondplace.
Table 3. Result of Council vote. For ‘BC score’, first preferences were given 5 points, second
preferences 4 points, etc. For ‘MBC score’, see explanation in text.
Because ‘Hackett’ had an overall majority of first preferences, it would have won the vote
straightaway if it had been conducted by first-past-the-post, PRSTV or multiple-round voting.3
Analysis by party
Because the ballotswere public,itispossible toobservedifferences invotingpatterns between and
within political parties. Table 4 shows the basic BC result for the eight categories of councillors.
Table 4. Breakdown by party / group, using basic BC. Top choice shown in red.
The onlyparty groupthat unanimouslyrankedone optionfirst(namely‘Hackett’)wasSinnFéin;
eveninthisgroup, secondandthirdpreferenceswere splitbetween‘Bermingham’and‘Mills’.The
Labour Partywas nearlyunanimousinitsfirstpreferencesfor‘Hackett’(15 of 17 voters);itsvote
became more fragmentedatlowerpreferences.The majorityof Fine Gael’sfirstpreferenceswentto
3 In multiple-round voting, voters choose one option in each round; the option with the lowest total is
eliminated and another round takes place. Voting continues until one option has a majority of votes. This
procedure is logically equivalentto PRSTV, provided voters do not change their preferences from one round to
the next. I mention this procedure sinceitmight have been employed if the Council had not used BC (Lacey,
Bermingh Duff Hackett Mills Stoker
first preferences 15 1 27 6 2
second preferences 11 1 7 25 6
third preferences 11 8 4 13 7
fourth preferences 7 16 5 3 11
fifth preferences 1 15 7 1 15
BC score 167 80 192 176 92
MBC score 156 76 165 156 90
Voters Bermingh Duff Hackett Mills Stoker
Eirígí 1 3 1 5 4 2
Fianna Fáil 6 24 11 14 28 7
Fine Gael 12 51 24 24 41 39
Independent 8 31 14 34 25 15
Labour 17 37 25 80 60 23
People Before Profit 1 4 0 5 0 0
Sinn Féin 5 17 5 25 18 6
United Left 1 0 0 5 0 0
‘Bermingham’andthe majorityof FiannaFáil’sto‘Mills’,butneitherof these partiesshowedany
evidence of coordinationatlowerpreferences,andinneitherof themwas‘Hackett’consistently
last.Overall, then, the datadosupporta readingof the vote as reflectingaleft-rightpolarity,since
nearlyall of the membersof partiesdefiningthemselvesasleftist4
preference, while nomemberof Fine Gael orFiannaFáil did – they,onaverage,ranked‘Hackett’just
a bit betterthanfourth.It isimportanttoemphasise,however,thatthe successof ‘Hackett’
dependedonitsbeingranked higherthanfifthbyeventhese voters.We shouldnot,therefore,read
the resultas a left-wing‘victory’butasindicatingthe centre of gravityinafieldwhere preferences
were certainlyclustered,butstill widelydispersed.
Some technical issues
All votingsystemshave theoretical anomalies,inthe sense thattheirresultscandependonfactors
that seemarbitrary accordingto democraticprinciples. One of the technical issueswiththe BCis
that the resultof a BC countcan be affectedbywhetherornotcertain losing optionsare on the
agendaat all,evenwhenthe voters’preferencesamongthe otheroptionsare unchanged.5
PRSTV and first-past-the postcarrythe same risk.) Was the final BCresultdependenton a shortlistof
five alternatives,ratherthan,say,fouror six?A close analysisof the results(notshownhere)
indicates thateliminatinganyof the fourlosingalternativeswouldnothave affectedthe outcome.6
However,itistheoreticallypossible thatif the shortlisthadcontained asixthoption,there could
have beena tie forfirstplace betweenHackettandMills usingthe basicBC method,anda victoryfor
MillsusingMBC. ThisresultisshowninTable 5.7
Table 5. Possible result in six-option contest. See text for details.
Since the BC isknownto be theoreticallyvulnerabletothiskindof result,we shouldnotbe too
surprisedbythisexample. Whatisreassuringinthe presentcase isthata problematicresult can
onlybe constructedbymeansof verystrictand unrealisticassumptions(see note 8foran
4 I.e. Eirígí, Labour, People Before Profit, Sinn Féin, United Left.
5 This is referred to in the academic literaturewith the unfortunate name of the principleof ‘independence of
6 This was tested by computing the resultof every four-option casethat included Hackett.
7 Table 5 is based on stipulatingthateveryone who preferred Mills to Hackett also preferred the sixth option to
Hackett, but everyone who preferred Hackett to Millsranked the sixth option last.Note that no changes have
been made to voters’ preferences among the original fiveoptions.Itis an accidentof the set of preferences
that the basic BC method generates a tie. If Hackett had won the original contestby a slightly lower margin,
Mills would havewon the six-option contest under both methods.
Bermingh Duff Hackett Mills Stoker AN Other
first preferences 15 1 27 6 2 0
second preferences 11 1 5 25 6 2
third preferences 10 8 2 13 6 5
fourth preferences 6 13 4 3 11 5
fifth preferences 3 12 5 1 12 7
sixth preferences 0 6 7 0 4 32
BC score 209 112 224 224 127 91
MBC score 198 108 197 204 125 61
A relatedissue is thatall votingsystemsare theoreticallyopentomanipulationby ‘strategicvoting’,
i.e. votingdifferentlyfromone’strue preferencesforthe sake of achievingamore favoured
outcome. Forexample,infirst-past-the-postsystems,itmakesstrategicsensetovote forone of the
twoleadingcandidates,evenif youwouldprefersomeone else. InaBC system, the apparently
obviousstrategyisto place the alternative youthinkof asyour biggestthreat atthe bottomof your
list, ,so as to maximise the gapbetween yourpreferredoptionandthatalternative.Inthe current
example,proponentsof ‘Mills’mighthave done soby ranking‘Hackett’ fifth, regardlessof their
actual preferences,whileproponentsof ‘Hackett’mighthave done the opposite.
It ishard to know whetheranycouncillors attemptedtovote strategically,butthe distributionof
preferencesdoesnotsuggestthatthiswasat all widespread.Forexample,therewasnoconsistent
patterninthe lowerpreferencesof voterswiththe same firstpreference.
We can, however, see what would have happened if everyone who ranked ‘Mills’ above ‘Hackett’
had bumped ‘Hackett’ down to fifth place, and vice versa. Table 6 shows the result.
Table 6. Result of simple strategic voting by ‘Mills’ and ‘Hackett’ supporters.
What isstrikinginthisresultisthat the strategywouldhave givenvictoryto ‘Bermingham’,an
alternative thatmanyvotersconsideredworse thaneither‘Hackett’ or‘Mills’. Infact,the outcome
of thiskindof strategicvotinginBC systemsis very unpredictable,because whenyoudropthe rank
of one rival,youraise the scoresof others.Supportersof BC argue that thisunpredictability
In a basicBC vote,anothersimpleformof strategicvotingisto refuse tovote for anyoptionyou
wouldnotlike towin,since thismaximisesthe differencebetweenthe pointsassignedtoone’s
favourite option(s) andthose others.Itispossible thatsome of the councillorswhoreturned
incomplete ballotswereactingstrategicallyinthisway,buttheymayalsohave been simply
indifferentamongthe remainingoptions.The factthat‘Hackett’wouldhave wonunderthe MBC
indicatesthatthisstrategy,if thatis whatit was,wasnot decisive in the presentcase. The effectof
thisstrategy isalso highly unpredictable:atitslimit(whereeveryvoterranksonlyone candidate),it
isequivalenttofirst-past-the-postanddefeatsthe purpose of aBC procedure. One of the
advantagesof the MBC isthat it eliminatesthisform of strategicvoting.
DublinCityCouncil’suse of the BordaCountto name itsnew bridge wasan important milestonein
decision-making.A detailedanalysisof itsresultsinboththe short-listingprocessandthe final
decisionshowsthatitperformeditspurpose effectively. Althoughtherewere significantparty-
Bermingh Duff Hackett Mills Stoker
first preferences 15 1 27 6 2
second preferences 22 3 5 9 8
third preferences 5 19 0 4 14
fourth preferences 3 20 0 1 18
fifth preferences 0 0 18 24 0
BC score 184 114 173 104 120
MBC score 175 111 145 98 120
political differencesinhowcouncillorsvoted,the BCsystemexhibitedone of itscentral virtues,
namely itschoice of an optionthathad at leastsome supportevenamongitsopponents.
The technical analysisof the vote givenabove indicatessome of the waysthat the outcomesof the
BC, like those of othersystems, canbe affectedbyseeminglyinsignificantissues,suchaswhether or
not a losingalternativeisonthe ballotandhow incomplete ballotsare treated.However, itseems
clearthat these issuesdidnotaffectthe outcome onthisoccasion. Although,like all voting
procedures,BCsystemsare inprinciple opentostrategicvoting,there isnoevidence inthe present
case of people votingstrategically,andthe case illustratesthe unpredictableeffectsof attemptingto
At the endof the day,what mattersisthat a votingprocedure reflects,asfaras possible,whatitis
tryingto measure.BordaCountproceduresattempttofindthe alternative (orsetof alternatives)
that has the mostsupportfrom the electorate,takingtheirentire setof preferencesintoaccount.
Choosingacommemorative name foranew bridge inthe centre of Dublinshouldsurelybe basedon
that kindof information.Itistherefore bothappropriateandadmirable thatDublinCityCouncil used
the Borda Countto make its decision.
DublinCityCouncil (2013a) 'MonthlyCityCouncil Meeting02/09/2013: Minutes',(Dublin:DublinCity
--- (2013b) 'Naming of New City Bridge: Report No. 272/2013', (Dublin: Dublin City Council).
Emerson, Peter (2012) Defining Democracy: Voting Procedures in Decision-Making, Elections and
Governance (2nd edn.; Heidelberg: Springer).