资源描述：
《ROC-likelihood ratio》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、STATISTICSINMEDICINEStatist.Med.2004;23:2257–2266(DOI:10.1002/sim.1835)Advantagestotransformingthereceiveroperatingcharacteristic(ROC)curveintolikelihoodratioco-ordinatesNilsP.Johnson∗;†CollegeofPhysiciansandSurgeons;ColumbiaUniversity;630W.168thSt.;NewYork;NY10032;U.S.A.SUMMARYTra
2、ditionally,thereceiveroperatingcharacteristic(ROC)curveforadiagnostictestplotstruepositives(sensitivity)againstfalsepositives(oneminusspecicity).However,thisrepresentationbringswithitseveraldrawbacks.Atransformationtopositiveandnegativelikelihoodratioco-ordinates,scaledbybase-tenl
3、ogarithms,oersseveraladvantages.Firstwemotivatetheuseofpositiveandnegativelikelihoodratios,emphasizingtheirrelationshiptomodicationoftheoddsratio.ThenwehighlightpropertiesoflikelihoodratiosusingthetraditionalROCaxes.Finally,wedemonstrateROCcurvesandtheirpropertiesafterconversiont
4、olikelihoodratioco-ordinates.Thesegraphsdonotwastespacefortestslackingdiagnosticpower,andoerasimplevisualassessmentofatest’simpactontheoddsratio.Copyright?2004JohnWiley&Sons,Ltd.KEYWORDS:receiveroperatingcharacteristic(ROC)curve;likelihoodratio;sensitivity;specicityINTRODUCTIONAd
5、iagnostictestrevisesthepre-testprobabilityofdiseaseviaapplicationofBayes’theo-rem[1].Forabinarydiagnostictest,apositiveresultrevisesthisprobabilityupwardswhileanegativeresultrevisesitdownwards.Toconvertacontinuousdiagnostictesttoabinaryone,rangesofresultsinthecontinuousvariablemust
6、beinterpretedaseitherpositiveornegative.Thechoiceofpositiveandnegativecut-osdeterminestheratesoftrueandfalsepositives,whencomparedtothegoldstandardfordiagnosingthedisease.Thetrueandfalsepositiverates,inturn,determinethemagnitudeofrevisiontothedisease’sprobability.Areceiveroperatin
7、gcharacteristic(ROC)curveplotsthetruepositiverateagainstthefalsepositiveratefordierentchoicesofcut-oranges[2].However,theseaxesobscuremorethantheyenlighten.First,halfoftheareashownonanROCplotcannotcontainanymeaningfulcurves.Thisdeceivestheeyeintominimizingareadierences.Second,it
8、requiressubstantialfamilia
