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ðstudy€of€the€distribution€and€determinants€of€health„related€statesÏand€events€in€populations€and€the€application€of€this€study€to€control€of€health€problems.ðð€ÏòòReference€Manual€on€Scientific€Evidenceóó,€Federal€Judicial€Center,€p.€174€(1994)(hereinafterÏð ðòòReference€Manualóóðð).ÌÌà àThere€are€two€general€types€of€epidemiological€studies€which€are€used€to€test€aÏhypothesis:€€(1)€cohort€studies€and€(2)€case„control€studies.€€In€a€cohort€study,€the€epidemiologistÏidentifies€a€group€of€individuals€who€have€been€exposed€to€the€chemical€and€another€group€ofÏindividuals€who€have€not€been€exposed€to€the€chemical.€€The€epidemiologist€chooses€two€groupsÏas€nearly€identical€as€possible€except€for€exposure€to€the€chemical.€€The€incidence€rates€ofÏdisease€of€the€exposed€and€non„exposed€groups€over€a€period€of€time€is€then€observed.€€A€case„control€study€involves€persons€who€either€have€the€disease€(cases)€or€do€not€have€the€diseaseÏ(controls).€€The€cases€and€controls€are€matched€for€comparison.€€A€determination€is€made€as€toÏwhether€the€individuals€in€the€case€and€control€groups€were€exposed€to€the€chemical.€€Ì BÝ ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€After€collecting€the€data€either€using€a€cohort€or€case„control€study,€epidemiologistsÏtypically€measure€risk€using€the€concepts€of€ð ðrelative€riskðð€and/or€ð ðodds€ratio.ðð€€Cohort€studies€yieldÏa€direct€measure€of€the€risk€of€brain€damage€according€to€the€presence€or€absence€of€solventÏexposure.€€This€direct€measure,€known€as€the€relative€risk,€is€the€ratio€of€the€incidence€of€brainÏdamage€or€ð ðtoxic€encephalopathyðð€in€the€exposed€group€divided€by€the€rate€in€the€nonexposed›Ïgroup.€€If€the€relative€risk€is€1.0,€then€there€is€no€association€between€solvent€exposure€and€brainÏdamage.€€A€relative€risk€of€4.0€indicates€that€the€risk€of€disease€in€the€exposed€group€is€four€timesÏhigher€than€the€risk€of€disease€in€the€unexposed€group.€€òòReference€Manualóó€at€148.€€By€contrast,Ïcase„control€studies€utilize€an€odds€ratio€in€calculating€risk.€€An€odds€ratio€is€based€on€aÏcomparison€of€the€odds€of€having€a€disease€when€exposed€to€a€suspected€agent€and€when€notÏexposed.€€òòReference€Manualóó€at€149.€€Relative€risk€and€odds€ratio€are€generally€similar€in€mostÏcases.€€€Ì ØÝ ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€Bakerððs€report€studied€among€others,€Hanninen›€(1991€&€1979);€Baker€(1988);€Arlien„Soberg€(1979);€Elofsson€(1980);€Hane€(1977);€Bleeker€(1991);€Bolla€(1990);€Parkinson€(1990);ÏMaizlsih€œ(1985);›€and€Spurgeon€(1992).Ì ØÝ ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€The€plaintiffsðð€fourth€expert,€Dr.€Michael€Kelly,€was€the€examining€physician€whoÏdiagnosed€the€plaintiffsðð€toxic€encephalopathy.€€He€described€the€ð ðdifferential€diagnosisððÏprocedure€he€used€in€this€regard.Ì ùÝ ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€Cross„sectional€studies€involve€selection€of€individuals,€regardless€of€exposure€orÏdisease€status.€€Subjects€for€such€studies€are€chosen€either€at€random€or€via€probability€samplingÏprocedures,€which€allows€for€the€examination€of€the€prevalence€of€a€disease€in€a€representativeÏsample€of€the€population.€€McCunney,€ð ðEpidemiology€and€Biostatics,ðð€òòA€Practical€Approach€toÏOccupational€and€Environmental€Medicine€óó€(2nd€Ed.),ðð€at€349€.€€Case€reports€are€notÏepidemiological€studies,€but€merely€reports€of€individuals€who€have€been€exposed€to€an€agentÏand€then€report€symptoms€associated€€with€the€disease.€€€Case€reports€usually€precede€theÏinstitution€of€formal€epidemiological€research,€although€they€can€be€important€in€determiningÏwhether€an€association€exists€between€an€agent€and€a€disease€or€defect.€€For€example,€theÏmedical€community€became€aware€of€the€association€between€the€drug,€Thalidomide,€used€byÏpregnant€women€as€a€sedative€and€birth€defects€in€their€children€as€a€result€of€case€reports.Ì ïÝ ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€Other€studies€referenced€by€the€parties€supporting€the€theory€include€Axleson,€et€al.,Ï1976;€Hanninen,€et€al.,€1976;€Hane,€et€al.,€1977;€Harkonen,€et€al.,€1977;€Knave,€et€al.,€1978;ÏMikkelson,€1980;€and€Gregersen,€et€al.,€1987,€among€others.Ì Ý ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€Ô€fXÔÒ ° ÒÒ ° ÒÑ ° ÑÑ ° ÑÝ  ÝÝ‚%ÿÝÔ€fÔÔ€fôÔÝ  ÝÔT€%ÔÔT€%$ÔOf€course,€scientific€evidence€also€must€be€relevant€before€it€is€admissible.€€As€stated€in€Tenn.€R.ÏEvid.€Rule€401,€ð ð[r]elevant›€evidence€means€evidence€having€any€tendency€to€make€the€existence€of€anyÏfact€that€is€of€consequence€to€the€determination€of€the€action€more€probable€or€less€probable€than€it€wouldÏbe€without€the€evidence.ððÌÝ‚%ÿÝÝ  Ý ?Ý ƒ!ÝÑ#€d#ÑÔ€fÔÝ  ÝÝ ƒÄ$ÝÓ  ÓÑ À ÑÑ Ì ÑÒ 4 ÒÒ „ ÒÔ€fÔÔ€fôÔò òà àòòÚ  ÚÚ  Úóóó óÝ  Ý€The€trial€judge€identified€four€different€standards€used€by€Tennessee€courts€toÏdetermine€admissibility€of€scientific€evidence:€(1)€ð ðScientifically€acceptable€and€accurate€for€itsÏpurpose.ðð€€òòState€v.€Johnson,óó€717€S.W.2d€298€(Tenn.€Crim.€App.€1986);€(2)€ð ðFour„prongÏthreshold€test€involving€whether€the€witness€is€an€expert;€whether€the€subject€matter€is€proper;Ïwhether€the€subject€matter€conforms€to€a€generally„accepted€theory;€and€whether€the€probativeÏvalue€of€the€witnessðð€testimony€outweighs€its€prejudicial€effect.ðð€€òòState€v.€Schimpfóó,€782€S.W.2dÏ186€(Tenn.€Crim.€App.€1989);€(3)€ð ðòòFryeóó€or€Tenn.€R.€Evid.€702€and€703.ðð€€òòState€v.€Harrisóó,€866ÏS.W.2d€583€(Tenn.€Crim.€App.€1992);€and€(4)€ð ðAnalysis€under€several€testsðð€òòState€v.€Myersóó,€1992ÏWL€297626€(Tenn.€Crim.€App.€1992).ÌPtPtHHÚ(ÿáÿâùFG(üHHÚ(d'hStyl{WP}01•ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃà Ãà Ãà Ãà Ãà ÃÃÃÃÃÃÃÃÃÃÃÐ ÐÐHHÐÐ  ÐÐ2ÐÐÿÿ¸æ$ÿÐÐHHÐÐÐÐÐÐÐÐ  ÐÐ ÐÐ ÐÑÑÑGenevaÑÑ ÑÑ € ÑÑ<Px–ÈÑÒÒÒ443!#4ÒÒ$ *$ÒÒ$*$ÒÒ ÿKK ÒÒ  Geneva ÒÒ  Geneva ÒÓ.,ÓÓÓÓ6ÓÓ ÓßßßßßßßßßßßßßßßßßßÑGenevaÑÑ ÑÒ  h HD: Geneva ÒÒ  h HD: Geneva Ò(­+2@x$¤¤Ý ƒ¤T!ÝÓ  ÓÝ  ÝÓ  ÓÑÀ°ÑÑ̰ÑÒ„°ÒÒ4°ÒÔ€XíŽXXHXÔÔ€òШòXXíŽÔò òà Œ àòòÚ  Ú0Ú  Úóóó óÝ ƒ!ÝÔ . ÔÔ€fÔÝ  ÝÒ ° ÒÒ „ ÒÑ  ÑÒ 4 ÒÒ „ ÒÑ\R AØ'\ÑÑ€ÑÑ  ÑÑ\R AØ'\Ñ›Ñ7€íŽXXdædÈ7ÑØ ØÓ&€XÐd&Óœ›Þ ÞÌà@ àIN€THE€SUPREME€COURT€OF€TENNESSEEÌÌà@ àAT€NASHVILLEÌÌÌÌÌÌà àà àà àà àà àà àà àœ€ò òòòFOR›€PUBLICATIONÌÌó óóóà àà àà àà àà àà à€€€€€€€€€ò òòòFiled:€œ€September€29,€1997ó ó›óóÌà àà àà àà àà àà àà àÌKENNETH€McDANIEL,à àà àà à)Ìà àà àà àà àà àà à)Ìà àPlaintiff„Appellee,à àà àà à)à àœ€DAVIDSON›€CIRCUITÌà àà àà àà àà àà à)à àÌà àà àà àà àà àà à)à àÌ€Vs.à àà àà àà àà àà à)€€€€€œ€HON.›€MARIETTA€M.€SHIPLEY,Ìà àà àà àà àà àà à)à àà à€€JUDGEÌà àà àà àà àà àà à)ÌCSX€TRANSPORTATION,€INC.,à àà à)Ìà àà àà àà àà àà à)Ìà àDefendant„Appellant.à àà à)€€€€€€œ€No.›€€01„S„01„9605„CV„00095̜ـÙßR€ijhA1-j|%+` ç `€€@ÿRß›ÌÌÌÌÌÌò òòòFor€Appellant:à àà àà àà àFor€Appellee:ó óóóÌÌœWayne€L.€Robbins,€Jr.›à àà àà àVan€Kirk€McCombs,€IIÌGareth€S.€Adenà àà àà àà àJames€H.€WettermarkÌGULLETT,€SANFORD,à àà àà àBURGE€&€WETTERMARK,€P.C.Ì€€ROBINSON€&€MARTIN,€PLLCà àà à2300€SouthTrust€TowerÌNashville,€Tennessee€€37219à àà àBirmingham,€Alabama€€35203„3204ÌÌEdward€H.€StopherÌBOEHL,€STOPHER€&€GRAVESÌSuite€2300,€Providian€CenterÌ400€West€Market€StreetÌLouisville,€Kentucky€€40202„3346ÌÌÌÌÌò òÔ€f„Ôà@ àO€P€I€N€I€O€Nó óÌÔ€fXÔÌÌÌÌÌÌœAFFIRMED.à àà à›à àà àà àà àà àœ€€€€€€ANDERSON,›€œC.€J.›ÇÓÓÑ  Ñà àWe€granted€this€interlocutory€appeal€to€clarify€the€standards€for€theÏadmissibility€of€scientific€evidence€under€Tennessee€Rules€of€Evidence€702€andÏ703.€€ÌÌà àThe€trial€court,€after€a€Tenn.€R.€Evid.€104€pretrial€evidentiary€hearing,Ïadmitted€into€evidence€the€testimony€of€plaintiffsðð€experts€who€relied€onÏepidemiological€studies€to€prove€that€exposure€to€organic€solvents€caused€aÏform€of€brain€damage€known€as€toxic€encephalopathy.€€The€trial€court€found€thatÏthis€scientific€evidence€would€substantially€assist€the€trier€of€fact€and€wasÏreliable€and€trustworthy.ÌÌà àThe€Court€of€Appeals€denied€an€interlocutory€appeal.€€We,€however,Ïgranted€the€interlocutory€appeal€and€conclude€that€Tennessee€Rules€ofÏEvidence€702€and€703€impose€a€duty€upon€trial€courts€to€determine€whetherÏscientific€evidence€will€substantially€aid€the€trier€of€fact€and€whether€theÏunderlying€facts€and€data€relied€on€by€the€œexpert›€witness€indicate€a€lack€ofÏtrustworthiness.€€The€trial€court€must€further€determine€whether€the€reasoning€orÏmethodology€underlying€the€scientific€evidence€is€sufficiently€valid€and€reliable,Ïand€whether€it€can€properly€be€applied€to€the€facts€at€issue.ÌÌà àIn€making€this€determination,€the€trial€court€should€focus€on€the€principlesÏand€methodology€underlying€the€science,€and€not€on€the€conclusions€of€experts.€ÍThe€trial€court€is€not€required€to€determine€that€the€principles€and€methodologyÏemployed€are€generally€accepted€by€the€scientific€community.€€The€court€needsÏonly€to€determine€that€the€principles€and€methodology€are€scientifically€validÏand€reliable.ÌÌà àWhen€these€standards€are€applied€in€this€case,€the€scientific€evidenceÏproffered€by€the€plaintiffs€should€be€admitted.€€Accordingly,€we€conclude€that€theÏtrial€court€did€not€abuse€its€discretion€in€denying€the€defendantððs€motion€inÏlimine€which€sought€to€exclude€the€plaintiffsðð€expert€testimony.ÌÌà@ àò òòòBACKGROUNDó óóóÌà àThis€case€involves€eighty„four€(84)€cases€filed€pursuant€to€the€FederalÏEmployers€Liability€Act,€45€U.S.C.€ðð€51,€òòetóó€œòòseqóó.,›€by€employees€of€the€defendantÏCSX€Transportation,€Inc.€(ð ðCSXTðð),€a€railroad€operator,€which€wereÏconsolidated€for€motions€and€case€management€in€the€Davidson€County€CircuitÏCourt.€€Each€plaintiff€alleges€that€he€has€suffered€brain€damage€due€to€chronicÏexposure€to€four€(4)€particular€organic€solventsœ× ƒk ××  ×›€while€working€in€the€CSXTÏmechanical€shops€in€Nashville,€Tennessee.€€ÌÌà àThe€plaintiffs€intend€to€rely€upon€occupational€physicians€to€show€thatÏlong„term,€low€dosage€exposure€to€the€solvents€has€caused€a€form€of€brainÏdamage€known€as€toxic€encephalopathy,€which€is€marked€by€diminished€short„term€memory,€sleeplessness,€depression€and€anxiety.€€The€plaintiffsðð€expertsÏrely€upon€epidemiological€studies,× ƒl ××  ×€which€they€contend€established€theÏcausation€between€long€term€exposure€to€solvents€and€damage€to€the€centralÏnervous€system.€€ÌÌà àCSXT€sought€to€exclude€the€plaintiffsðð€experts€on€the€basis€that€theirÏtestimony€was€without€sufficient€scientific€support.€€CSXT€contended€that€theÏepidemiological€studies€relied€on€by€the€plaintiffs€did€not€consistently€establishÏa€causal€connection€with€a€relative€risk€or€odds€ratio€that€shows€a€statisticallyÍsignificant€degree€of€reliability.œ× ƒm ××  ×›€€It€concluded,€therefore,€that€the€proffered€expertÏtestimony€on€the€issue€would€not€ð ðsubstantially€assistðð€the€trier€of€fact,€and€thatÏthe€facts€and€data€underlying€the€testimony€shows€a€ð ðlack€of€trustworthiness.ðð€€€ÌÌà àAt€a€pretrial€Tenn.€R.€Evid.€104€evidentiary€hearing,€several€expertÏwitnesses€for€the€plaintiff€and€the€defendant€offered€their€opinions€concerningÏthe€effect€of€long„term€exposure€to€low€doses€of€the€organic€solvents€involved€inÏthis€litigation.€€The€proof€indicated€that€the€solvents€belong€to€a€family€of€organicÏsolvents€known€as€chlorinated€hydrocarbons,€while€mineral€spirits€are€generallyÏdistilled€from€petroleum€products.€€The€industrial€utility€of€the€solvents€lies€inÏtheir€ability€to€dissolve€grease.€€ÌÌà àThe€experts€agreed€that€there€is€no€objective€diagnostic€tool,€(such€as€anÏMRI,€CT€Scan,€or€X„Ray),€that€will€support€a€diagnosis€of€toxic€encephalopathy,Ïand€that€no€biological€mechanism€has€been€identified€that€demonstrates€howÍexposure€to€the€solvents€causes€the€damage.€€Moreover,€while€the€expertsÏagreed€that€acute€exposure€to€high€concentrations€of€the€solvents€can€createÏdizziness,€disorientation,€and€even€unconsciousness,€the€allegations€in€thisÏcase€involve€exposure€below€the€level€necessary€to€render€a€personÏunconscious.€€ÌÌà àOne€of€the€plaintiffsðð€experts,€Dr.€Edward€Baker,€a€physician€specializingÏin€occupational€medicine€with€two€œmasters›€degrees,€one€in€public€health€andÏanother€in€epidemiology,€testified€œthat›€he€has€authored€twenty„six€articles€andÏfour€textbook€chapters€on€the€subject€of€the€effects€of€exposure€to€solvents.€€HeÏbegan€studying€the€effects€of€solvent€exposure€on€the€central€nervous€systemÏwhile€on€the€faculty€of€Harvard€Universityððs€School€of€Public€Health.€€He€hasÏsummarized€epidemiological€studies€conducted€since€1985€and€has€concludedÏthat€ð ðthese€cross€sectional€studies,€viewed€in€the€aggregate,€support€the€viewÏthat€chronic€solvent€exposure€causes€impairment€of€neurobehavioral€function.ðð€ÏBaker,€ð ðA€Review€of€Recent€Research€on€Health€Effects€of€Human€OccupationalÏExposure€to€Organic€Solvents,ðð€òòJournal€of€Occupational€Medicineóó,€Vol.€36,€No.Ï10€(Oct.€1994).œ× ƒn ××  ×›€€Baker€testified€that€dose/response€and€degree€of€exposureÏwere€critical€to€the€causation€inquiry.€€€€ÌÌà àAnother€plaintiffsðð€expert,€Dr.€Douglas€Linz,€also€a€physician€specializingÏin€occupational€medicine,€has€authored€four€articles€on€the€effects€of€exposureÏto€solvents€and€has€diagnosed€patients€with€chronic€encephalopathy.€€LikeÏBaker,€he€has€performed€and€reviewed€the€epidemiological€studies€on€theÏsubject€and€has€concluded€that€ð ðchronic€low€dose€exposure€to€solvents€canÏcause€chronic€encephalopathy.ðð€€Dr.€Howard€Frumkin,€a€physician€with€aÏdoctorate€in€public€health,€has€evaluated€patients€for€solvent€exposure,€and€hasÏresearched€and€written€on€the€effects€of€exposure€on€the€central€nervousÏsystem.€€He€testified€that€a€sufficient€degree€of€exposure€over€a€sufficientÏamount€of€time€can€cause€toxic€encephalopathy,€and€that€the€diagnosis€ofÏchronic€encephalopathy€from€low€dose€exposure€to€solvents€is€generallyÏaccepted€throughout€the€United€States€and€the€world.× ƒo ××  ×ÌÌà àIn€contrast,€Dr.€Philip€Edelman€testified€on€behalf€of€the€defendant€thatÏalthough€dose€response€is€critical€to€any€toxicology€study,€ð ðmostðð€in€the€medicalÏcommunity€of€toxicologists€did€not€accept€the€causal€connection€between€lowÏdose€exposure€to€solvents€and€encephalopathy.€€€Edelman,€a€physician€who€isÏboard€certified€in€toxicology€and€occupational/environmental€medicine,Ícriticized€the€epidemiological€studies€that€the€plaintiffsðð€experts€relied€upon€forÏlacking€a€good€dose/response€relationship€and€for€failing€to€control€forÏconfounding€factors€such€as€age,€intelligence,€and€the€use€of€alcohol.€€Likewise,ÏDr.€Joseph€McLaughlin,€a€Ph.D.€in€epidemiology,€testified€that€theÏepidemiological€studies€on€the€relation€between€exposure€to€solvents€and€toxicÏencephalopathy€failed€to€account€for€significant€confounding€factors.€€Finally,€Dr.ÏRobert€James,€a€Ph.D.€in€pharmacology,€testified€that€he€reviewed€forty„fiveÏcross€sectional€studies€and€determined€that€œ84€percent›€supported€theÏhypothesis€and€œ16€percent›€did€not.€€He€criticized€the€ð ðpositiveðð€studies,€however,Ïfor€failing€to€account€for€the€factors€of€age,€intelligence,€experience,€and€alcoholÏconsumption.€€In€Jamesððs€opinion,€the€diagnosis€of€toxic€encephalopathy€fromÏexposure€to€solvents€was€not€generally€accepted€in€the€medical€community.ÌÌà àAfter€considering€the€testimony€of€the€experts€and€analyzing€the€pertinentÏstudies,€the€trial€court€concluded€that€the€proposed€evidence€was€ð ðgrounded€inÏscientific€theory,ðð€€was€ð ðgenerally€accepted€in€the€occupational€healthÏcommunity,ðð€and€was€trustworthy€and€reliable.€€Although€denying€theÏdefendantððs€motion€to€exclude€the€expert€testimony,€the€trial€court€recognizedÏthe€need€to€develop€a€uniform€and€consistent€body€of€law€and€granted€theÏdefendantððs€motion€for€an€interlocutory€appeal€pursuant€to€Tenn.€R.€App.€P.€9.€ÏAlthough€the€Court€of€Appeals€denied€the€interlocutory€appeal,€we€granted€theÍappeal€to€clarify€the€standards€for€determining€the€admissibility€of€scientificÏevidence€in€this€jurisdiction.€€We€now€affirm€the€trial€court.Ì€Ìà@ àò òòòSCIENTIFIC€LITERATUREÌó óóóà àWe€begin€our€analysis€by€reviewing€the€relevant€material€that€wasÏsubmitted€to€the€trial€court€and€discussed€by€several€of€the€experts€during€theÏevidentiary€hearing.€€In€the€1970's,€researchers€in€certain€ScandinavianÏcountries,€performing€epidemiological€studies€using€case€report€and€cross„sectional€methods,× ƒp ××  ×€reported€that€neuropsychiatric€symptoms€may€be€inducedÏby€long„term€exposure€to€solvents.€€In€1979,€the€Danish€physician,€Arlien„Soborg,€coined€the€phrase€ð ðchronic€paintersðð€syndrome,ðð€in€a€study€done€onÏseventy€house€painters.€€The€report€concluded€that€the€majority€of€the€paintersÏwho€had€been€exposed€to€organic€solvents,€often€through€a€period€with€acuteÏintoxication€symptoms,€had€gradually€developed€signs€of€a€chronic€brainÏsyndrome.€€€The€symptoms€included€impaired€memory,€fatigue,€personalityÏchange,€headaches,€and€irritability.€€Arlien„Soborg,€et€al.,€ð ðChronic€PaintersððÍSyndrome€„€Chronic€Toxic€Encephalopathy€in€House€Painters,ðð€òòActa.€œNeurol.ÏScandóó,›€60:149„156€(1979).€€Other€authors,€including€plaintiffsðð€expert€Dr.ÏEdward€Baker,€have€reported€that€the€Scandinavian€studies€supported€theÏhypothesis€that€toxic€encephalopathy€occurs€in€individuals€heavily€exposed€toÏsolvents€over€a€period€of€months€to€years.€€òòSeeóó€Baker,€et€al.,€ð ðThe€NeurotoxicityÏof€Industrial€Solvents:€A€Review€of€the€Literature,€ð ð€òòAm.€J.€of€Indus.€Med.óó,€8:207„217€(1985).œ× ƒq ××  ×›ÌÌà àAs€the€defendant€contends,€the€Scandinavian€studies€have€beenÏcriticized€for€failing€to€prove€that€the€paintersðð€symptoms€were€related€to€theirÏoccupational€exposure€to€organic€solvents€and€œfor€the€disappearance›€ofÏevidence€of€impairment€in€œtwenty›€re„examined€workers.€€òòSeeóó€Errebo„KnudsenÏand€Olsen,€ð ðOrganic€Solvents€and€Presenile€Dementia€(The€PaintersððÏSyndrome):€A€Critical€Review€of€the€Danish€Literature,ðð€òòThe€Sci.€of€the€TotalÏEnvððtóó,€48:45„67(1986);€Gade€et€al.,€ð ðChronic€Painterððs€Syndrome.€€A€ReanalysisÏof€Psychological€Test€œData›€in€a€Group€of€Diagnosed€Cases,ðð€òòActa€Neurol.ÏScandóó.,€77:293„306€(1988).€ÌÌà àSome€studies€have€likewise€questioned€the€Scandinavian€studies.€€AsÏone€report€indicates:ÌÓÓà8 àœÌà8 àStudies›€outside€Scandinavia,€mainly€cross„sectional€clinicalÏstudies,€have€not€supplied€convincing€evidence€to€support€theÏhypothesis€of€solvent€exposure€causing€irreversible€brain€damageÏœ..›€.€œ.€The›€reason€for€this€discrepancy€might€lie€in€differences€ofÏstudy€design,€incomparable€study€populations,€insufficientÏadjustment€for€confounding€factors,€and,€perhaps€most€importantly,Ïdifferences€in€disease€classification.ÌÌÌÓÓRasmussen€et€al.,€ð ðSolvent„Induced€Chronic€Toxic€Encephalopathy,ðð€òòAm.€J.€OfÏIndust.€Med.óó,€23:779„792€(1993);€òòseeóó€òòalsoóó€œWilliamson,›€et€al.,€ð ðA€ProspectiveÏCohort€Study€of€the€Chronic€Effects€of€Solvent€Exposure,ðð€òòEnvironmental€Res.óó,Ï62:256„271€(1993)(ð ðcross€sectional€studies€suffer€from€problems€of€possibleÏconfounding€by€a€range€of€unknown€factors€and€also€usually€from€poorÏestimates€of€exposure.ðð).€€Moreover,€other€studies€have€reached€oppositeÏresults.€€òòSeeóó,€òòe.g.óó,€Spurgeon,€et€al.,€ð ðInvestigation€of€Dose€RelatedÏNeurobehavioral€Effects€in€œPaintmakers›€Exposed€to€Low€Levels€of€Solvents,ððÏòòOccupational€&€Environmental€Medicineóó,€51:626„630€(1994)(cross€sectionalÏstudy€of€110€paintmakers€resulted€in€view€that€ð ðlong€term€exposure€at€or€belowÏcurrent€compliance€levels€does€not€result€in€damage€to€the€central€nervousÏsystem.ðð).ÌÓ` °ŽX'0*ŒXÓÌ€à àDespite€the€criticisms,€textbooks€and€review€articles€recognize€theÏdiagnosis€of€toxic€encephalopathy.€€For€example,€in€the€chapter€entitledÏð ðOrganic€Solvents€and€Related€Compoundsðð€of€the€òòTextbook€of€ClinicalÏOccupational€and€Environmental€Medicineóó,€the€authors€state€that€ð ðthere€isÏcurrently€sufficient€support€for€the€association€of€high€long„term€solventÏexposure€with€long„lasting€psycho„organic€symptoms€to€consider€this€a€clinicalÏreality.ðð€€Rosenstock€and€Cullen,€at€p.€773€(1994).€ÌÌà àInternational€and€national€governmental€health€organizations€also€haveÏrecognized€the€syndrome.€€For€example,€at€the€World€Health€Organization€andÏNordic€Council€of€Ministers€meeting€in€Copenhagen,€Denmark,€in€June€1985,€itÏwas€stated€that€ð ð[c]linical,€epidemiological€and€experimental€data€indicate€thatÏlong„term€occupational€exposure€to€organic€solvents€may€cause€adverse€effectsÏin€the€central€and€the€peripheral€nervous€systems.ðð€€It€was€recommended€thatÏfurther€ð ðclinical,€experimental€and€epidemiological€studies€should€beÏundertaken€to€gain€further€insight€into€the€reversibility€of€the€neurotoxic€effectsÏinduced€by€the€solvents,€their€health€significance€and€the€dose„effect,€dose„response€relationships.ðð€€òòIdóó.€at€pp.€32„33.ÌÌà àThe€National€Institute€for€Occupational€Safety€and€Health€(ð ðNIOSHðð)Ïð ðCurrent€Intelligence€Bulletin€œ48,ð ð›€issued€on€March€31,€1989,€makes€similarÏobservations€and€œrecommends›€that€producers€and€users€inform€their€customers,Íthat€trade€associations€and€unions€warn€their€workers,€and€that€protectiveÏequipment€and€worker€education€be€used€to€reduce€worker€exposure€„„€at€leastÏto€concentrations€specified€in€exposure€lists€of€OSHA€and€other€œorganizations.›€€ÏòòIdóó.€at€iii„iv.ÌÌà àAccordingly,€as€the€trial€court€found,€numerous€epidemiological€studiesÏsupport€the€diagnosis€of€toxic€encephalopathy€from€exposure€to€solvents.€€WhileÏother€reports€have€criticized€the€epidemiological€studies,€the€diagnosis€isÏrecognized€in€textbooks€and€journals,€as€well€as€by€national€and€world€healthÏorganizations.€€It€is€with€this€background€that€we€now€turn€to€the€legal€principlesÏgoverning€the€admissibility€of€scientific€evidence.€ÌÌà@ àò òòòSCIENTIFIC€EVIDENCEÌó óóóà àNearly€75€years€ago,€the€test€for€determining€the€admissibility€of€scientificÏevidence€was€established€in€the€landmark€federal€case€of€òòFrye€v.€United€Statesóó,Ï293€F.€1013€(D.C.€Cir.€1923).€€In€òòFryeóó,€which€involved€a€polygraph€examination,Ïor€lie€detector,€the€court€said€that€scientific€evidence€will€be€admissible€only€if€itÏhas€ð ðgained€general€acceptance€in€the€particular€field€in€which€it€belongs.ðð€€òòIdóó.€atÏ1014.€€This€rule,€although€followed€by€the€vast€majority€of€federal€and€stateÏjurisdictions,€including€Tennessee,€€was€often€criticized€for€being€too€restrictiveÏof€relevant€evidence,€particularly€new€or€ð ðcutting€edgeðð€scientific€theory,€and€tooÍvague€for€uniform€application.€€òòSeeóó€òòe.g.óó,€òòSymposium€on€Science€and€the€RulesÏof€Evidenceóó,€99€F.R.D.€188€(1983)(and€extensive€authority€discussed€therein).€€€ÌÌà àThe€federal€courts€embarked€on€a€new€and€less€restrictive€course€withÏthe€decision€recently€in€òòDaubert€v.€Merrell€Dow€Pharmaceuticalsóó,€509€U.S.€579,Ï113€S.Ct.€2786,€125€œL.Ed.2d›€469€(1993),€by€the€U.€S.€Supreme€Court€where€theÏCourt€reversed€the€9th€Circuit€and€determined€that€the€ð ðgeneral€acceptanceðð€testÏset€forth€in€òòFryeóó€was€superseded€by€Fed.€R.€Evid.€702:€ÌÓÓà8 àÌà8 àIf€scientific,€technical,€or€other€specialized€knowledge€will€assistÏthe€trier€of€fact€to€understand€the€evidence€or€to€determine€a€fact€inÏissue,€a€witness€qualified€as€an€expert€by€knowledge,€skill,Ïexperience,€training,€or€education,€may€testify€thereto€in€the€form€ofÏan€opinion€or€otherwise.ÌÌÌÓÓAccording€to€the€Court,€Rule€702€requires€a€determination€as€to€ð ðwhether€theÏexpert€is€proposing€to€testify€regarding€scientific€knowledge€that€will€assist€theÏtrier€of€fact€to€understand€or€determine€a€fact€in€issue.ðð€€òòDaubertóó,€509€U.S.€atÏ592,€113€S.Ct.€at€2796.€€This€determination€requires€the€trial€court€to€considerÏð ðwhether€the€reasoning€or€methodology€underlying€the€testimony€is€scientificallyÏvalid€and€of€whether€the€reasoning€or€methodology€properly€can€be€applied€toÏthe€facts€in€issue.ðð€€òòIdóó.€€In€analyzing€scientific€validity€or€reliability,€the€trial€courtÏmust€focus€on€€ð ðprinciples€and€methodology,€and€not€on€the€conclusions€theyÏgenerate.ðð€€òòIdóó.,€509€U.S.€at€595,€113€S.Ct.€at€2797.ÌÌà àA€partial€list€of€factors€the€Supreme€Court€deemed€relevant€to€the€inquiryÏincluded€whether€the€theory€or€technique€has€been€tested,€whether€it€has€beenÏsubject€to€peer€review€or€publication,€whether€there€is€a€known€or€potential€rateÏof€error,€and€whether,€as€formerly€required€under€òòFryeóó,€it€is€generally€acceptedÏin€the€relevant€scientific€field.€€òòIdóó.,€509€U.S.€at€593„94,€113€œS.Ct.›€at€2796„2798.€ÏOn€remand,€the€Ninth€Circuit€Court€of€Appeals€also€considered€whether€theÏexpert€proposes€to€testify€about€research€conducted€independent€of€litigation€orÏwhether€the€expert€had€formulated€an€opinion€for€the€express€purpose€ofÏtestifying.€€òòDaubert€v.€Merrell€Dow€Pharmaceuticals,€Inc.óó,€43€F.3d€1311,€1317Ï(9th€Cir.)(ð ðDaubert€IIðð),€òòcert.óó€òòdeniedóó,€116€S.Ct.€œ189,€133€L.Ed.2d€126›€(1995).ÌÌà àòòDaubertóóððs€influence€was€felt€in€òòJoiner€v.€General€Electric€Co.óó,€78€F.3dÏ524,€530€(11th€Cir.€œ1996),€òòcertóó.€òògrantedóó€117€S.Ct.€1243,€137€L.Ed.2d€325Ï(1997).›€€There,€the€trial€court€ruled€that€the€plaintiff€could€not€present€expertÏtestimony€that€his€exposure€to€polychlorinated€biphenyls€had€caused€lungÏcancer€and€granted€the€defendantððs€motion€for€summary€judgment.€€On€appeal,Ïthe€Eleventh€Circuit,€applying€òòDaubertóó,€emphasized:€€ÌÓÓà8 àÌà8 àIn€analyzing€the€admissibility€of€expert€testimony,€it€is€important€forÏtrial€courts€to€keep€in€mind€the€separate€functions€of€judge€andÏjury,€and€the€intent€of€òòDaubertóó€to€loosen€the€strictures€of€òòFryeóó€andÏmake€it€easier€to€present€legitimate€conflicting€views€of€experts€forÏthe€juryððs€consideration.ÌÌÌÓÓThe€court€stressed€the€trial€courtððs€role€was€a€narrow€one:ÌÓÓà8 àÌà8 àThis€gatekeeping€role€is€simply€to€guard€the€jury€from€consideringÏas€proof€pure€speculation€presented€in€the€guise€of€legitimateÏscientifically„based€expert€opinion.€€It€is€not€intended€to€turn€judgesÏinto€jurors€or€surrogate€scientists.€€òòThus,€the€gatekeepingÏresponsibility€of€the€trial€courts€is€not€to€weigh€or€choose€betweenÏconflicting€scientific€opinions,€or€to€analyze€and€study€the€scienceÏin€question€in€order€to€reach€its€own€scientific€conclusions€from€theÏmaterial€in€the€field.€€Rather,€it€is€to€assure€œthat›€expertððs€opinionsÏare€based€on€relevant€scientific€methods,€processes,€and€data,Ïand€not€on€mere€speculation,€and€that€they€apply€to€the€facts€inÏissueóó.ÌÌÌÓÓòòIdóó.€at€530€(emphasis€added).€€After€applying€the€òòDaubertóó€inquiry€and€analyzingÏthe€principles€and€methodology€underlying€the€plaintiffððs€scientific€evidence,€theÏEleventh€Circuit€Court€of€Appeals€held€that€the€trial€court€erred€in€excluding€theÏevidence.ÌÌà àAlthough€the€federal€courts€have€decided€a€new€and€less€restrictiveÏdirection€was€appropriate,€state€courts€are€still€wrestling€with€the€choiceÏbetween€òòFryeóó€and€òòDaubertóó.€€For€example,€in€a€case€involving€the€exact€sameÏparties,€issues,€and€experts€as€the€present€case,€a€Florida€state€circuit€court,Ïapplied€the€òòFryeóó€test,€which€was€retained€in€that€jurisdiction€by€the€FloridaÏSupreme€Court,€and€concluded€that€the€epidemiological€studies€wereÏinconsistent€and€that€the€criticisms€of€these€studies€„€that€the€plaintiffs€had€failedÍto€show€the€evidence€was€ð ðgenerally€acceptedðð€in€€the€relevant€scientificÏcommunity€„€were€valid€and,€therefore,€ruled€that€the€evidence€wasÏinadmissible.€€òòSeeóó€òòRoy€Lee€Berry€v.€CSX€œTransportation,›€Inc.óó,€No.€92„2167Ï(filed€April€28,€1995).€€ÌÌà àOn€the€other€hand,€in€a€federal€case€involving€the€exact€same€parties,Ïissues,€and€experts€as€the€subject€case,€the€federal€district€court€for€theÏSouthern€District€of€Georgia€applied€òòDaubertóó,€and€concluded€that€the€evidenceÏwas€admissible.€€The€district€court€found€that€the€epidemiological€studiesÏsupported€the€œplaintiffððs›€claim€that€exposure€can€cause€impairment,€and€foundÏthat€the€studies€and€results€were€scientifically€valid€and€reliable€notwithstandingÏthe€criticisms€by€opposing€experts€and€reports.€€The€court€rejected€theÏdefendantððs€claim€that€the€œplaintiffs›€must€show€causation€with€a€relative€risk€orÏodds€ratio€of€2.0€or€greater.€€òòSeeóó€òòBob€œAllen,›€et€al.€v.€CSX€œTransportation,›€Inc.óó,Ï(S.D.€Ga.,€filed€Sept.€10,€1996).ÌÌÌà@ àò òòòTHE€TENNESSEE€STANDARDó óóóÌà àAfter€examining€the€basic€legal€principles€governing€the€admissibility€ofÏscientific€evidence€and€the€change€in€direction€by€the€federal€courts,€we€turn€toÏTennessee€to€clarify€our€standard€of€admissibility.ÌÌà àIn€general,€questions€regarding€the€admissibility,€qualifications,Ïrelevancy€and€competency€of€expert€testimony€are€left€to€the€discretion€of€theÏtrial€court.€€òòState€v.€Ballardóó,€855€S.W.2d€557,€562€(Tenn.€1993).€€The€trial€courtððsÏruling€in€this€regard€may€only€be€overturned€if€the€discretion€is€arbitrarilyÏexercised€or€abused.€€òòIdóó.€€The€specific€rules€of€evidence€that€govern€the€issue€ofÏadmissibility€of€scientific€proof€in€Tennessee€are€Tenn.€R.€Evid.€702€and€703.œ× ƒr ××  ×›€ÏThe€former€provides:€€ÌÓÓà8 àÌà8 àIf€scientific,€technical,€or€other€specialized€knowledge€willÏsubstantially€assist€the€trier€of€fact€to€understand€the€evidence€or€toÏdetermine€a€fact€in€issue,€a€witness€qualified€as€an€expert€byÏknowledge,€skill,€experience,€training,€or€education€may€testify€inÏthe€form€of€an€opinion€or€otherwise.ÌÌÌAnd€Tenn.€R.€Evid.€703€states:ÌÌÌà8 àThe€facts€or€data€in€the€particular€case€upon€which€an€expertÏbases€an€opinion€or€inference€may€be€those€perceived€by€or€madeÏknown€to€the€expert€at€or€before€the€hearing.€€If€of€a€typeÏreasonably€relied€upon€by€experts€in€the€particular€field€in€formingÏopinions€or€inferences€upon€the€subject,€the€facts€or€data€need€notÏbe€admissible€in€evidence.€€The€court€shall€disallow€testimony€inÏthe€form€of€an€opinion€or€inference€if€the€underlying€facts€or€dataÏindicate€lack€of€trustworthiness.ÌÌÌÓÓà àThe€plaintiffs€contend€that€the€expert€testimony€in€this€case€is€reliable€andÏthat€it€will€substantially€assist€the€jury€on€the€issue€of€causation.€€The€defendantÏargues€that€irrespective€of€òòFryeóó€or€òòDaubertóó,€there€must€be€adherence€to€the€strictÏrequirements€contained€in€the€language€of€the€rules€and€also€a€reasonableÏstandard€for€proving€causation.€€It€contends€that€the€plaintiffsðð€scientific€evidenceÏis€unreliable€and€must€be€excluded.€€The€defendant€argues€that€anÏepidemiological€study€must€show€a€relative€risk€of€greater€than€2.0,€whichÏseveral€courts€have€said€means€that€a€disease€more€likely€than€not€was€causedÏby€the€specific€agent€or€event.€€òòSeeóó€òòDaubert€v.€Merrell€Dow€Pharmaceuticals,ÏInc.óó,€43€F.3d€1311€(9th€Cir.€1995),€òòcertóó.€òòdeniedóó,€116€S.Ct.€189,€133€L.Ed.2d€126Ï(1995);€òòDeluca€v.€Merrell€Dow€Pharmaceuticals,€Inc.óó,€791€F.Supp.€1042€(D.N.J.Ï1992),€òòaffððdóó,€6€F.3d€778€(3rd€Cir.€1993).€€As€discussed€herein,€the€factor€isÏcertainly€relevant€but€we€reject€the€contention€that€it€should€be€adopted€asÏmatter€of€law.€ÌÌà àAlthough€the€advisory€comments€to€Rule€702€indicate€that€TennesseeÏhas€followed€the€òòFryeóó€test€in€analyzing€the€admissibility€of€scientific€evidence,Ïone€commentator,€recognizing€the€similarity€between€Tennessee€Rule€702€andÏFederal€Rule€Evid.€702,€has€raised€the€question€of€whether€the€òòFryeóó€test€ofÏð ðgeneral€acceptanceðð€should€be€abolished€in€Tennessee.€€œN.€Cohen,›€œS.ÏSheppeard,€and€D.€Paine,›€òòTennessee€Law€of€Evidenceóó,€ðð€œ401.20€at€124,›€n.Í233.€€€Indeed,€as€the€trial€court€in€this€case€noted,€there€is€some€evidence€of€aÏdeparture€from€the€strict€adherence€to€the€òòFryeóó€test€by€courts€in€this€State.œ× ƒs ××  ×›€ÌÌà àIn€our€view,€determining€the€standard€for€the€admissibility€of€scientificÏevidence€requires€an€analysis€of€the€unique€language€found€in€Rules€702€andÏ703€of€the€Tennessee€Rules€of€Evidence.€€For€instance,€Tenn.€R.€Evid.€702Ïrequires€that€the€scientific€evidence€ð ðòòsubstantiallyóó€assist€the€trier€of€fact,ðð€whileÏits€federal€counterpart€requires€only€that€the€evidence€ð ðassist€the€trier€of€fact.ðð€ÏFed.€R.€Evid.€702.€€€This€distinction€indicates€that€the€probative€force€of€theÏtestimony€must€be€stronger€before€it€is€admitted€in€Tennessee.€€òòSeeóó,€òòe.g.óó,ÏWeinstein,€òòRule€702€of€the€Federal€Rules€of€Evidence€is€Sound;€It€Should€NotÏBe€Amendedóó,€138€F.R.D.€631,€636€(1991).€ÌÌà àSimilarly,€Tenn.€R.€Evid.€703€states€that€ð ð[œt]he›€court€shall€disallowÏtestimony€in€the€form€of€an€opinion€or€inference€if€the€underlying€facts€or€dataÏindicate€lack€of€trustworthiness.ðð€€There€is€no€similar€restriction€in€the€federalÏrule.€€Fed.€R.€Evid.€703.€€Thus,€as€one€writer€has€observed,€ð ðthe€additionalÍœlanguage€...›€[in€the€Tennessee€rule]€is€obviously€designed€to€encourage€trialÏcourts€to€take€a€more€active€role€in€evaluating€the€reasonableness€of€theÏœexpertððs›€reliance€upon€the€particular€basis€for€his€or€her€testimony.ðð€€R.€Banks,ÏòòSome€Comparisons€Between€the€New€Tennessee€Rules€of€Evidence€and€theÏFederal€Rules€of€Evidence,€Part€IIóó,€20€œMem.S.U.€L.€Rev.›€499,€559€(1990).€€InÏsum,€even€though€the€facts€and€data€need€not€be€admissible,€they€must€beÏreviewed€and€found€to€be€trustworthy€by€the€trial€court.€€ÌÌà àBased€on€the€foregoing€analysis,€we€conclude€that€TennesseeððsÏadoption€of€Rules€702€and€703€in€1991€as€part€of€the€Rules€of€EvidenceÏsupersede€the€general€acceptance€test€of€òòFryeóó.€€In€Tennessee,€under€the€œrecentÏrules,›€a€trial€court€must€determine€whether€the€evidence€will€substantially€assistÏthe€trier€of€fact€to€determine€a€fact€in€issue€and€whether€the€facts€and€dataÏunderlying€the€evidence€indicate€a€lack€of€trustworthiness.€€The€rules€togetherÏnecessarily€require€a€determination€as€to€the€scientific€validity€or€reliability€of€theÏevidence.€€Simply€put,€unless€the€scientific€evidence€is€valid,€it€will€notÏsubstantially€assist€the€trier€of€fact,€nor€will€its€underlying€facts€and€data€appearÏto€be€trustworthy,€but€there€is€no€requirement€in€the€œrule›€that€it€be€generallyÏaccepted.ÌÌà àAlthough€we€do€not€expressly€adopt€òòDaubertóó,€the€non„exclusive€list€ofÏfactors€to€determine€reliability€are€useful€in€applying€our€Rules€702€and€703.€€AÍTennessee€trial€court€may€consider€in€determining€reliability:€€(1)€whetherÏscientific€evidence€has€been€tested€and€the€methodology€with€which€it€has€beenÏtested;€(2)€whether€the€evidence€has€been€subjected€to€peer€review€orÏpublication;€(3)€whether€a€potential€rate€of€error€is€known;€(4)€whether,€asÏformerly€required€by€òòFryeóó,€the€evidence€is€generally€accepted€in€the€scientificÏcommunity;€and€(5)€whether€the€expertððs€research€in€the€field€has€beenÏconducted€independent€of€litigation.€€ÌÌà àAlthough€the€trial€court€must€analyze€the€science€and€not€merely€theÏqualifications,€demeanor€or€conclusions€of€experts,€the€court€need€not€weigh€orÏchoose€between€two€legitimate€but€conflicting€scientific€views.€€The€courtÏinstead€must€assure€itself€that€the€opinions€are€based€on€relevant€scientificÏmethods,€processes,€and€data,€and€not€upon€an€expertððs€mere€speculation.€ÏòòSeeóó,€òòe.g.óó,€òòJoineróó,€78€F.3d€at€530.€€€The€trial€court€should€keep€in€mind€that€theÏpreliminary€question€under€Tenn.€R.€Evid.€104€is€one€of€admissibility€of€theÏevidence.€€Once€the€evidence€is€admitted,€it€will€thereafter€be€tested€with€theÏcrucible€of€vigorous€cross„examination€and€countervailing€proof.€€After€thatÏoccurs,€a€defendant€may,€of€course,€challenge€the€sufficiency€of€the€evidence€byÏmoving€for€a€directed€verdict€at€the€appropriate€times.€€òòSeeóó€Tenn.€R.€Civ.€P.€50.€ÏYet€it€is€important€to€emphasize€that€the€weight€to€be€given€to€stated€scientificÏtheories,€and€the€resolution€of€legitimate€but€competing€scientific€views,€areÍmatters€appropriately€entrusted€to€the€trier€of€fact.€€òòSeeóó€òòJoineróó,€78€F.3d€at€534„35Ï(Birch,€J.,€concurring).ÌÌà àWe€recognize€that€the€burden€placed€on€trial€courts€to€analyze€and€toÏscreen€novel€scientific€evidence€is€a€significant€one.€€No€framework€exists€thatÏprovides€for€simple€and€practical€application€in€every€case;€the€complexity€andÏdiversity€of€potential€scientific€evidence€is€simply€too€vast€for€the€application€of€aÏsingle€test.€€òòSeeóó€òòDevelopments€in€the€œLaw€„„›€Confronting€the€New€ChallengesÏof€Scientific€Evidenceóó,€108€Harv.€L.€Rev.€1481,€1513„1516€(1995).€ÏNonetheless,€the€preliminary€questions€must€be€addressed€by€the€trial€court,Ïòòseeóó,€Tenn.€R.€Evid.€104,€and€they€must€be€addressed€within€the€framework€ofÏrules€702€and€703.€ÌÌ€€àH¤¤¤àò òòòà@ àAPPLICATION€OF€STANDARDó óóóÌà àThe€trial€court€correctly€foresaw€the€trend€away€from€òòFryeóó€and€also€usedÏthe€factors€set€forth€in€òòDaubertóó€as€a€framework€for€analysis.€€As€it€observed,€theÏscientific€theory€that€exposure€to€solvents€may€cause€toxic€encephalopathy€hasÏbeen€tested€frequently€over€a€period€of€25€years.€€Because€no€preciseÏdiagnostic€device€or€biological€mechanism€can€isolate€the€causal€factor,€theÏrelevant€tests€have€been€epidemiological€studies.€€The€experts€in€this€caseÏtestified€at€length€about€the€field€of€epidemiology€and€the€use€of€cohort€andÏcase„control€studies.€€The€experts€agreed€that€epidemiological€studies€haveÍbeen€used€to€test€the€hypothesis€that€exposure€to€solvents€causesÏencephalopathy€and€that€numerous€studies€support€a€causal€relationship.€ÏThese€studies€have€been€reviewed,€reconstructed,€published€in€leadingÏjournals€in€the€field,€and€subjected€to€peer€review.€€Although€the€ð ðpositiveððÏstudies€have€been€criticized€for€failing€to€account€for€confounding€factors,€theÏdiagnosis€is€recognized€in€medical€textbooks€and€journals€as€well€as€by€severalÏnational€and€world€health€organizations.€€We€also€observe€that€the€research€inÏthis€area,€including€that€of€several€of€the€plaintiffsðð€experts,€was€conductedÏindependently€of€this€litigation.ÌÌà àAccordingly,€we€agree€with€the€trial€courtððs€finding€that€the€evidence€willÏsubstantially€assist€the€jury€to€understand€the€evidence€and€to€determine€a€factÏin€issue.€€We€also€agree€with€the€trial€courtððs€conclusion€that€the€methodologyÏand€principles€underlying€the€scientific€evidence€are€sufficiently€trustworthy€andÏreliable€to€be€presented€to€the€trier€of€fact.€€The€trial€court€is€not€required€toÏdetermine€whether€it€agrees€with€the€evidence€and€should€not€substitute€its€viewÏfor€the€trier€of€fact.€€It€should€allow€the€jury€to€consider€legitimate€but€conflictingÏviews€about€the€scientific€proof.€€€Provided€the€evidence€is€scientifically€valid,Ïcriticisms€of€it€and€opposing€views€may€be€elicited€on€cross€examination€and/orÏestablished€in€the€defendantððs€case.€€That€is€the€essence€of€the€lawsuit.ÌÌà@ àò òòòCONCLUSIONóóó óÌà àWe€have€concluded€that€the€scientific€evidence€proffered€by€the€plaintiffsÏsatisfies€the€requirements€of€Tenn.€R.€Evid.€702€and€703,€and€that€the€trial€courtÏdid€not€abuse€its€discretion€in€admitting€it€into€evidence.€€The€trial€courtððs€orderÏdenying€the€defendantððs€motion€in€limine€is€therefore€affirmed€and€this€case€isÏremanded€to€the€trial€court€for€further€proceedings.€€Costs€of€the€appeal€areÏassessed€against€the€defendant.Ìà àà à€€€€€ÌÓÓà àà àà àà àà à________________________________ÌÓ)` °‰X? „XB')0*ŒX)Óà àà àà àà àà àE.€RILEY€ANDERSON,€CHIEF€JUSTICEÌÌ̛̜Ìò òÓ,"` °‰X? „X÷&')0*ŒX,ÓœConcur:ó 󛀀œÌÌDrowota,›€Reid,€Birch€and€Holder,€œJJ.›Ìœ›