 that can be assigned to various methodological properties are constrained. With QATs, on the other hand, the weight assigned to any methodological property is completely open, and can be determined based on rational arguments regarding the respective importance of the various properties, without arbitrary constraints imposed by the structure of the scoring system. In short, despite the widespread use of evidence hierarchies and the defense of such use by Howick (2011), and despite the problems that I raise for QATs above, QATs are superior to evidence hierarchies for assessing the great volume of evidence in contemporary medical research. 7 Conclusion An examination of QATs suggests that coarse-grained features of evidence in medicine, like freedom from systematic error, are themselves amalgams of a complex set of considerations; that is why QATs take into account a plurality of methodological features such as randomization and blinding. The various aspects of a specific empirical situation which can influence an assessment of a coarse-grained evidential feature are numerous, often difficult to identify and articulate, and if they can be identified and articulated (as one attempts to do with QATs), they can be evaluated by different scientists to varying degrees and by different quality assessment tools to various degrees. In short, there are a variety of features of evidence that must be considered when assessing evidence, and there are numerous and potentially contradictory ways to do so. Our best theories of scientific inference 22 provide little guidance on how to weigh the relevant methodological features included in tools like QATs. A group of medical scientists prominent in the literature on QATs notes that "the quality of controlled trials is of obvious relevance to systematic reviews" but that "the methodology for both the assessment of quality and its incorporation into systematic reviews are a matter of ongoing debate" (Jüni, Altman, and Egger, 2001). I have argued that the use of QATs are important to minimize arbitrariness when assessing medical evidence and to accurately estimate probabilities associated with measures of confirmation. However, available QATs vary in their constitutions, and when medical evidence is assessed using QATs their inter-rater reliability and intertool reliability is low. This, in turn, is a compelling illustration of a more general problem: the underdetermination of evidential significance. Disagreements about the strength of evidence are, of course, ubiquitous in science. Such disagreement is especially striking, however, when it results from the employment of carefully codified tools designed to quantitatively assess the strength of evidence. QATs are currently the best
that can be assigned to various methodological properties are constrained. With QATs, on the early bridge player, the weight assigned to any methodological place is completely candid, and can be determined based on intellectual argument regarding the respective importance of the assorted properties, without arbitrary constraints levy by the structure of the scoring arrangement. In short, despite the widespread use of evidence hierarchies and the defense of such function by Howick (2011), and despite the problems that I raise for QATs above, kat are superior to evidence hierarchies for measure the great bulk of evidence in contemporary medical research. 7 Conclusion An examination of QATs suggests that coarse - granulate features of evidence in medicine, like freedom from systematic error, are themselves amalgams of a complex set of considerations; that is why QATs take into account a plurality of methodological features such as randomization and blinding. The various aspects of a specific empirical situation which can influence an appraisal of a coarse - grained evidential feature are numerous, much unmanageable to name and articulate, and if they can be identified and articulated (as one attempts to do with QATs), they can be evaluated by different scientists to vary degrees and by different quality assessment tools to various degree. In short, there are a variety of features of evidence that must be consider when tax evidence, and there are numerous and potentially contradictory ways to serve so. Our best theories of scientific inference 22 leave little guidance on how to weigh the relevant methodological features admit in tools like kat. A group of medical scientists prominent in the literature on QATs notes that " the quality of control trials is of obvious relevance to taxonomic reviews " but that " the methodology for both the assessment of timbre and its incorporation into systematic reviews are a matter of ongoing debate " (Jüni, Altman, and Egger, 2001). I have argue that the use of kat are important to minimize arbitrariness when assessing aesculapian evidence and to accurately estimate probabilities associated with measures of ratification. However, available QATs vary in their constitutions, and when medical evidence is assessed using QATs their inter - rater reliability and intertool reliability is depleted. This, in turn, is a compelling illustration of a more general problem: the underdetermination of evidential significance. Disagreements about the strength of evidence are, of path, omnipresent in skill. Such disagreement is especially dramatic, however, when it results from the employment of cautiously codified tools designed to quantitatively assess the strength of evidence. QATs are currently the best
 thwt can be assigned to vavious methodolognxal prmpertiss are cunstrained. With QATs, on the ltyer hqnd, the weight assignea to any lethodoligicel property is completeln opeh, and ran be determingd based on sational argumangs regarding the respective importancq of thr garious properjies, eythohn crbitrary constraints imposed bg the suructure of the scpring system. In short, desplte hhe widespread use of evidencg hiqearchies and the defense of such uae by Howick (2011), and despite the pfobleks that I tcuse xor QATs abive, QWTs are supevpor to avidencr hierarchies nor avsewsing the great volumx of evidence in conjemporary kebical research. 7 Conclysuon At exdminxriov or AAFs sughesvs that coadse-grained deatures of evidenct ig medicine, liks freeqoi from systematic error, are themselves dmamgams of a complex set if considerations; thaj is why QWTs take into account a plurality of methodologicdl feetjrew fjxh as randomization and blinding. The various as[scus pf a specific cmpirical situatiom ahosh can influevce an asaessment of a coarde-graingd evieential ftaturr are numerous, often difficylt to identpfy qnd articulate, and if they cau be icentigied and articulated (as one attempts tl do with DATs), they can be evslgated by different scientifts to vacying degreer anc by dyfferent qkalitn assessment tools ho vatious gegrees. In short, there are a variety of fxetures of evicetce that muft be considered wren assessing gvidence, cnd thdre are nujerous end potentiajly contradicdlry ways to vo so. Our besr thwories uw scientific imference 22 provide luttle guidance on mow tu weigh the relercnu nethodological fextuwed mncluqad in tools nike QAGx. A gfoup of medlcau scoentists prominent it ths literature on QAYs notes tyat "the zuality of comtrolled trials is of ouvious relefanse to systematic reviews" but tgat "the mfthjdology for foth the assessmznt of quality and its incorporation inti systematic revigws are a matter of ougping debate" (Jüni, Wltman, ang Egger, 2001). I have arguwd that the use on QATs are important tk minikize wrbitrariness when assessing medical evidence and to accurately estimate probabmlyties assocjatec witv izasures of roifirmation. Howeveg, available QATs vary in their cunstituthous, and when medical evidence os assessed usivg QATs their inter-rater reliabikity and intertool reliability os low. This, in turn, is a compellung imlustratioi of a more general lroblek: the underdwterlination of exidrnbial signivicaice. Disagreements about the strengty of ecifence are, of coucse, ubiquitoms in sbience. Fuch disagreemenf is fspeckally strikinb, however, when it results from the eiployment of cqgefully codifoed toons designed vo quantitathvely assess the strength of evidence. QATs are currgntly the btst
that can be assigned to various methodological constrained. QATs, on other hand, the property completely open, and be determined based rational arguments regarding the respective importance the various properties, without arbitrary constraints imposed by the structure of the scoring In short, despite the widespread use of evidence hierarchies and the defense of use Howick and the problems that I raise for QATs above, QATs are superior to evidence hierarchies for assessing great volume of evidence in contemporary medical research. Conclusion An examination of suggests that coarse-grained features of in like freedom systematic are amalgams of a set of considerations; that is why QATs take into account a plurality of methodological features such as and blinding. aspects of specific situation can influence an a coarse-grained evidential feature are numerous, identify and articulate, and if they can be and articulated one attempts to do with QATs), can be evaluated by different scientists to varying and by different quality assessment tools to various degrees. In short, there are a variety of evidence that must considered when assessing and are and contradictory ways do so. Our best theories of scientific inference 22 provide little on how to weigh the relevant methodological features included in QATs. group of medical prominent in the literature QATs that "the quality of is obvious reviews" that methodology for both the of quality and its incorporation systematic reviews are a Altman, and Egger, 2001). I have argued that use of QATs are important to minimize when assessing medical evidence and to accurately estimate probabilities associated with measures confirmation. However, vary in their constitutions, and when medical evidence assessed using QATs their reliability and intertool reliability is low. This, in turn, a illustration of more general problem: underdetermination of evidential Disagreements about the evidence are, course, in is especially striking, however, when it from employment of carefully codified tools to the strength of evidence. QATs are currently the best
 that can be assigned to variouS methodoloGical ProPerTiEs arE conStrained. With QAtS, on tHe other hand, the weight asSigneD tO Any mEThOdoloGical prOPeRTY is CoMpLetElY OpEn, and Can Be deterMined based On rAtIonal argumenTS rEgarding thE reSpective impoRtaNce of tHe VarIOus prOpeRties, WithouT ArbitrAry constrAiNTs impoSEd by the STRuCturE of the scoring systEM. IN Short, despite thE widesPrEAd USE of EviDence hieraRcHies aND the defENsE OF SucH Use by Howick (2011), anD despite the PRobLems thAt i raISe for QaTs abOvE, qATS are superioR to eVidence hiErarchIEs for asSEssing tHe greaT voLumE of eVIdEnCe iN cONteMPoRarY MedIcal reseArCh. 7 conclUsioN aN EXamiNatIon oF QATs Suggests that cOarSe-grAIneD featUres oF eviDeNce in MediciNe, likE fReedom from systeMatiC error, are TheMsElvEs AmalgAMs of a cOmpLex Set of coNsideraTIonS; tHAT Is Why QATs take into accOuNT A pLurality Of methODoLoGIcal featUrEs sUch aS RAndomIzatIOn And blindIng. The VArIoUs aspecTs Of a speCiFic EmpIricaL SituAtion wHich can iNflueNCe an assessment OF a coarse-grainED eVIDeNTial FeaTure are numeRous, OFten DiffICuLt tO IdentIfy anD aRTiCUlate, and if they can be IdEntifiEd and Articulated (as One attemptS TO Do with QAts), thEY cAN be evaluated by DiffeRent scientISts to varYing dEgrees anD by differENT quality AssEssMenT toOLS tO various degreES. in shOrT, there aRe a Variety Of fEatUreS of EvIdence thaT must be cOnSiDeReD whEn assESsing eviDeNce, AnD thEre arE NumeroUs and PoteNtIaLLy cOntradiCToRY Ways To Do So. OuR beSt TheorIes oF SciEntific Inference 22 ProVIde lItTlE guidanCe on how to weigH tHe relevant MeThoDologiCAL featureS included in tools like QATS. a group oF meDical ScieNtists proMinEnt in tHe lITeratuRe on QAts notEs ThaT "THe quaLITy Of cOnTrolled triALS is Of obvIoUs reLevance To systematic reviewS" But That "the methodOloGy foR BOtH thE AsSEssMeNT of QUAlity and its incoRporation iNtO SyStematic reVIewS aRe a mattEr of ongOing dEBate" (JünI, Altman, anD Egger, 2001). I haVe ArguED ThaT the use of QaTs are imPortant to MInimiZE aRbitrAriNess whEn AssEssinG medicAL evIdencE and to AcCurateLy estImAte probaBilities associated with mEasureS of coNfiRmation. HoWevER, avAilable QAts vaRy in their cOnsTitUtionS, anD When mEdicAL eVidENce is AsseSSed using Qats TheIR InTer-rater relIABIliTy and IntERtool rEliaBility is low. This, in TUrn, is a compelliNg ilLUStrAtiON of a MoRe general problEm: tHe UNDerdeterMiNation of eviDential sIgNIficaNce. DisAgreemEnts aboUT ThE StrengTh of EviDence are, oF coUrSE, ubiquiToUs IN scienCe. SuCh DisagrEement IS espECIally striking, howEver, wHEN it reSUltS from ThE employMEnt oF carefully Codified tooLs desiGned To quaNtitatiVeLy asseSs tHe Strength of EVidence. QAts are CurrentLy The bEst
 that can be assigned to v arious met hodol ogi cal  p rope rtie s are constrai n ed.With QATs, on the othe r han d, thew ei ght a ssigned to a nyme th odo lo g ic al pr ope rty iscompletely  op en , and can be de termined b ase d on rationa l a rgumen ts  re g ardin g t he re specti v e impo rtance of  t h e vari o us prop e r ti es,without arbitrary co n straints impos ed byth e  s t r uct ure  of the sc or ing s y stem. I n  s h o r t,d espite the wi despread us e  of  evide nc e h i erarch ies a nd the  defense of  suc h use byHowick (2011), and des pite t hepro blem s  t ha t I  r a ise fo r Q A Tsabove, Q AT sare s uper i o r to e vid ence  hier archies for a sse ssin g  th e gre at vo lume  o f evi dencein co nt emporary medica l re search. 7  Co nc lus io n Ane xamina tio n o f QATssuggest s  th at c o ar se-grained feature so f  e videncein med i ci ne ,  like fr ee dom  fro m syste mati c  e rror, ar e them s el ve s amalg am s of a  c omp lex  seto f co nsider ations;thati s why QATs tak e  into account ap l ur a lity  of  methodolog ical feat ures su cha s ran domiz at i on and blinding. The v ar ious a spect s of a specif ic empiric a l situatio n wh i ch can influencean as sessment o f  a coars e-gra ined evi dential f e a ture are  nu mer ous , o f t en  difficult to i dent if y and a rti culate,  an d i f t hey  c an be ide ntifiedan dar ti cul ated( as one a tt emp ts  to  do w i th QAT s), t heyca nb e e valuate d  b y diff er en t sc ien ti sts t o va r yin g degre es and by  di f fere nt  q ualityassessment to ol s to vario us  de grees. I n short,  there are a variety of feature s o f evi denc e that mu stbe con sid e red wh en ass essin gevi d e nce,a n dthe re  are numer o u s a nd po te ntia lly con tradictory ways to doso. Our bestthe orie s of  sc i en t ifi ci nfe r e nce 22 providelittle gui da n ce  on how to wei gh  the re levantmetho d ologica l feature s include din t o o lslike QATs.  A group  of medic a l sci e nt istspro minent  i n t he li teratu r e o n QAT s note sthat " the q ua lity ofcontrolled trials is of  obvio us re lev ance to s yst e mat ic review s" b ut that "t hemet hodol ogy for b otht he  as s essme nt o f  qualitya nd  it s in corporation i n tosyste mat i c revi ewsare a matter of o n going debate"(Jün i ,  Al tma n , an dEgger, 2001).I h av e argued t ha t the use o f QATs a re impor tant t o mini mize ar b i tr a riness  whe n a ssessingmed ic a l evide nc ea nd toaccu ra tely e stimat e  pro b a bilities associa ted w i t h mea s ure s ofco nfirmat i on.However, a vailable QA Ts var y in  thei r const it utions , a nd  when medi c al eviden ce is  assess ed  usi ngQATs t heir i nter- rate rrel iabilitya n di nt er t ool  rel iabil it y is  low. Thi s , in tur n,i s a com pe lli n g  illus t ra t i on of a mo regener a l  problem:t he u n de r deter minati on ofevident i alsi gnifica nce . Disagreem ents abou t  th estre ngth ofev iden ce  ar e,  of course, ubi quitousin scien c e . Such  di s agre e ment i sespecially s triki ng ,  howeve r ,  wh en it r e sul tsfro m th e e mplo y ment of carefully codifi ed t oolsd esi gnedto qu an titative l y as sess the strength of e vidence. QATs a r e c u rren tly th ebest
 that_can be_assigned to various methodological_properties are_constrained._With QATs,_on_the other hand,_the weight assigned_to any methodological property_is completely open,_and_can be determined based on rational arguments regarding the respective importance of the various_properties,_without arbitrary_constraints_imposed_by the structure of the_scoring system. In short, despite_the widespread_use of evidence hierarchies and the defense of_such_use by Howick_(2011), and despite the problems that I raise for_QATs above, QATs are superior to_evidence hierarchies for_assessing_the_great volume of evidence_in contemporary medical research. 7 Conclusion_An examination of QATs suggests that_coarse-grained features of evidence in medicine, like_freedom from systematic error, are themselves_amalgams of a complex set_of considerations;_that is why QATs take_into account a_plurality of_methodological features such_as randomization and blinding. The various_aspects of a_specific empirical situation which can influence_an_assessment of a_coarse-grained_evidential_feature are_numerous, often difficult_to_identify and_articulate,_and if they can be identified_and_articulated (as one attempts to do with_QATs), they can be_evaluated_by different scientists to_varying degrees and by different_quality assessment tools to various degrees._In short,_there are_a variety of features of evidence that must be considered when_assessing evidence, and there are numerous_and potentially contradictory ways_to do_so._Our best theories_of_scientific inference_22 provide little guidance on how to_weigh the_relevant methodological features included in tools_like QATs. A group_of_medical scientists prominent in the literature_on QATs notes that "the quality_of controlled trials is of_obvious_relevance_to systematic reviews" but that_"the methodology for both the assessment_of quality and_its incorporation into systematic reviews are a_matter_of ongoing debate" (Jüni, Altman, and_Egger,_2001). I have argued that the_use_of_QATs are important to minimize_arbitrariness when assessing medical evidence and_to accurately estimate probabilities associated with measures of confirmation._However, available QATs_vary in their constitutions, and_when_medical_evidence is assessed using QATs their inter-rater reliability and intertool_reliability is_low. This, in_turn, is a compelling illustration of a more general problem:_the underdetermination of evidential significance. Disagreements about_the strength of evidence are, of course, ubiquitous in science. Such_disagreement is especially striking, however, when it results_from the employment of carefully codified tools_designed to quantitatively assess_the_strength of evidence. QATs are currently the_best