Avague-set-basedfuzzymulti-objectivedecisionmakingmodelisdevelopedforevaluatingbiddingplansinabid-dingpurchaseprocess.Agroupofdecision-makers(DMs)firstindependentlyassessbiddingplansaccordingtotheirexperienceandpreferences,andtheseassessmentsmaybeexpressedaslinguisticterms,whicharethenconvertedtofuzzynumbers.Theresultingdecisionmatricesarethentransformedtoobjectivemembershipgradematrices.Thelowerboundofsatisfactionandupperboundofdissatisfactionareusedtodetermineeachbiddingplan’ssupporting,opposing,andneutralobjectivesets,whichtogetherdeterminethevaguevalueofabiddingplan.Finally,ascorefunctionisemployedtorankallbiddingplans.Anewscorefunctionbasedonvaguesetsisintroducedinthemodelandanovelmethodispresentedforcalculatingthelowerboundofsat-isfactionandupperboundofdissatisfaction.Inavague-set-basedfuzzymulti-objectivedecisionmakingmodel,differentvalua-tionsforupperandlowerboundsofsatisfactionusuallyleadtodistinctrankingresults.Therefore,itiscrucialtoeffectivelycontainDMs’arbitrarinessandsubjectivitywhenthesevaluesaredetermined.