 the strength of the evidence generated from those studies. One might agree with the view that there is no uniquely best QAT, but be tempted to think that this is due only to the fact that the quality of a study depends on particularities of the context (e.g. the particular kind of study in question and the form of the hypothesis being tested by that study). Different QATs might, according to this thought, be optimally suited to different contexts. While this latter point is no doubt true-above I noted that some QATs are designed for assessing particular kinds of studies, and others are designed for assessing studies in particular domains of medicine-it does not explain the low inter-tool reliability of QATs. That is 16 because, as above, the low inter-tool reliability of QATs is demonstrated in narrowly specified contexts. Moreover, the research groups that design QATs usually claim (explicitly) that their QATs are meant to be applicable to a given study design (usually RCTs) in almost any domain of medical research. In short, QATs are intended to apply to a broad range of contexts, but regardless, the empirical demonstrations of their low inter-tool reliability are almost always constrained to a single particular context. Despite their widespread and growing use, among medical scientists there is some debate about whether or not QATs ought to be employed at all (see, for example, Herbison et al. (2006)). Their low inter-rater and inter-tool reliability might suggest that resistance to their use is warranted. There are three reasons, however, that justify the continuing improvement and application of QATs to assessing the quality of medical evidence. First, when performing a meta-analysis, a decision to not use an instrument to differentially weight the quality of the primary-level studies is equivalent to weighting all the primary-level studies to an equal degree. So whether one wishes to or not, when performing a meta-analysis one is forced, in principle, to weight the primary-level studies, and the remaining question then is simply how arbitrary one's method of weighting is. Assigning equal weights regardless of methodological quality is maximally arbitrary. The use of QATs to differentially weight primary-level studies is an attempt to minimize such arbitrariness. Second, as argued in §2 above, one must account for fine-grained methodological features in order to guarantee that one avoids potential defeating properties of evidence, and QATs can help with this.
the strength of the evidence generated from those studies. One might agree with the opinion that there be no uniquely best QAT, but be tempted to think that this is ascribable only to the fact that the quality of a study depend on particularities of the context (e.g. the especial kind of study in question and the shape of the hypothesis being tested by that discipline). Different QATs might, according to this thought, be optimally suited to different contexts. While this latter detail is no doubt true - above I noted that some QATs are design for assessing particular kinds of studies, and others are plan for assessing studies in particular domains of medicine - it does not excuse the low inter - tool reliability of QATs. That is 16 because, as above, the low inter - tool reliability of QATs is demonstrated in narrowly specified context. Moreover, the research groups that design QATs usually claim (explicitly) that their QATs are meant to be applicable to a given study design (normally RCTs) in about any domain of medical research. In light, QATs are intended to apply to a wide range of contexts, but regardless, the empirical demonstrations of their gloomy inter - tool reliability are almost always constrained to a unmarried particular context. Despite their widespread and growing use, among aesculapian scientists there be some argument about whether or not QATs ought to be use at all (see, for example, Herbison et al. (2006) ). Their gloomy inter - rater and inter - tool reliability might suggest that resistance to their use is warranted. There are three reasons, however, that justify the proceed improvement and application of QATs to assessing the quality of medical evidence. First, when perform a meta - analysis, a decisiveness to not use an instrument to differentially burden the quality of the primary - horizontal surface studies is equivalent to slant all the primary - level studies to an equal degree. So whether one wishes to or not, when performing a meta - analysis one is coerce, in principle, to weight the chief - level studies, and the remaining question then is simply how arbitrary one's method of weight is. Assigning equal weights regardless of methodological quality is maximally arbitrary. The use of QATs to differentially weight primary - degree report is an attempt to minimize such flightiness. Second, as argued in § 2 above, one must account for fine - ingrain methodological features in order to guarantee that one avoids potential defeating properties of evidence, and QATs can help with this.
 thf strength of the evidenge generated from those studiss. One mkght agree with the view thav thwre iw no uniquely best QAT, but be tvmpted to thiik that this is vhe only to ths facc vhat the qualiti of a study depends on pastkcblarities of the context (e.g. the partycular lijd of study in quexeion and the form of the hypothesis bejng tesued by that study). Cifferent QATs might, accorfing to this thought, bf optimally suiewd to differdnt contexus. While thia latter point is no doubt true-xbove I noted tyar slke QATs are desidned for asscxsing [articukar kinds of sbudiev, abd others are designev for assessing studyes in pastncular domains of meducune-it doev nog exolajn tge low inver-tool reljability of QATs. That is 16 becaisq, as above, the low igtqr-tool reliability of QATs is demonstraued ih narrowly specified cobtexts. Moreover, the rgsearch grjups that design QATs usually claim (explicitly) thdt thxif QCBf qrf meant to be applicable to a given study desyfn (uxually RCTs) in almost any dlmsyn of medical reseaxdh. In short, QATs are intendgd to qpply to w brpad range of contexts, but rwgardless, thv empirical demonstratnons of theix low onter-yool reliability are aloost always condtrained fu a single partizulsr context. Despite their widqspread aid grpwing ure, akong mqdical scifntisbv there is some dehate cbout whether og not QATs ought to be employed at all (see, fot efamile, Herbifon eb al. (2006)). Their low inter-rater anb inter-tjol rdliability might vuggest thae resistance dl their use ms warraneed. Rherw are tffee reasons, hoeever, than lustify tye continuing imprpveosnt and applicacnob of QATs to asxesrind nhe qtdlity of medhcal evkcence. First, when oerfprming a meta-analysiv, a secision to not usr wn instroment to qifferentiallu weight the qualiuy of vhe prmmary-lrvej studies is equivalent to weifhting alp tme primary-levql sbudigs to an eqbal degree. So whether one wishes to or nit, when performing a meta-analysis one ls forced, in prinsiple, to feight the primary-lecel studies, and tme remaining question fhen iv simoly how arbitrary one's method of weighting is. Assigning equal weights regqrdless of methodomogival qlalnty is mavimapuy arbitrary. The use of QATs to differentially xeight prikaxy-level studies is an attempt tu minimize suzh arbitrariness. Second, zs arguec in §2 above, one must account fot fine-grained methodologlcal featyres jn ordvt tu guarantee that ome avonds porential defcating propertkes on evidence, and QCTs can help with this.
the strength of the evidence generated from One agree with view that there but tempted to think this is due to the fact that the quality a study depends on particularities of the context (e.g. the particular kind of in question and the form of the hypothesis being tested by that study). QATs according this be optimally suited to different contexts. While this latter point is no doubt true-above I noted some QATs are designed for assessing particular kinds studies, and others are for assessing studies in particular of does not the inter-tool of QATs. That 16 because, as above, the low inter-tool reliability of QATs is demonstrated in narrowly specified contexts. Moreover, research groups QATs usually (explicitly) their are meant to to a given study design (usually any domain of medical research. In short, QATs intended to to a broad range of contexts, regardless, the empirical demonstrations of their low inter-tool are almost always constrained to a single particular context. Despite their widespread and growing use, scientists there is some about whether or QATs to employed all (see, example, Herbison et al. (2006)). Their low inter-rater and inter-tool reliability suggest that resistance to their use is warranted. There are however, justify the continuing and application of QATs assessing quality of medical evidence. performing meta-analysis, not an to differentially weight the of the primary-level studies is to weighting all the degree. So whether one wishes to or not, performing a meta-analysis one is forced, in to weight the primary-level studies, and the remaining question then is simply arbitrary one's weighting is. Assigning equal weights regardless of methodological is maximally arbitrary. The of QATs to differentially weight primary-level studies is an to such arbitrariness. as argued in above, one must for fine-grained methodological order to that avoids of evidence, and QATs can help this.
 the strength of the evidence gEnerated frOm thoSe sTudIeS. One MighT agree with the vIEw thAt there is no uniquely besT QAT, bUt BE temPTeD to thInk that THiS IS duE oNlY to ThE FaCt thaT thE qualitY of a study dEpeNdS on particulaRItIes of the coNteXt (e.g. the partiCulAr kind Of StuDY in quEstIon anD the foRM of the HypothesiS bEIng tesTEd by thaT STuDy). DiFferent QATs might, aCCoRDing to this thouGht, be oPtIMaLLY suIteD to differeNt ConteXTs. While THiS LATteR Point is no doubT true-above I NOteD that sOmE QAtS are deSigneD fOR asSessing partIculAr kinds of StudieS, And otheRS are desIgned fOr aSseSsinG StUdIes In PArtICuLar DOmaIns of medIcInE-it doEs noT EXPLain The Low iNter-tOol reliabilitY of qATs. tHat Is 16 becAuse, aS aboVe, The loW inter-Tool rElIability of QATs iS demOnstrated In nArRowLy SpeciFIed conTexTs. MOreover, The reseARch GrOUPS tHat design QATs usualLy CLAiM (expliciTly) thaT ThEiR qATs are mEaNt tO be aPPLicabLe to A GiVen study Design (USuAlLy RCTs) iN aLmost aNy DomAin Of medICal rEsearcH. In short, qATs aRE intended to appLY to a broad rangE Of CONtEXts, bUt rEgardless, thE empIRicaL demONsTraTIons oF theiR lOW iNTer-tool reliability aRe Almost AlwayS constrained tO a single paRTICular conText. dEsPIte their widespRead aNd growing uSE, among meDical ScientisTs there is SOMe debate AboUt wHetHer OR NoT QATs ought to bE EMploYeD at all (sEe, fOr exampLe, HErbIsoN et Al. (2006)). their low iNter-rateR aNd InTeR-toOl relIAbility mIgHt sUgGesT that REsistaNce to TheiR uSe IS waRranted. tHeRE Are tHrEe ReasOns, HoWever, That JUstIfy the cOntinuing ImpROvemEnT aNd appliCation of QATs tO aSsessing thE qUalIty of mEDIcal evidEnce. First, when performing A Meta-anaLysIs, a deCisiOn to not usE an InstruMenT To diffErentiAlly wEiGht THE qualITY oF thE pRimary-leveL STudIes is EqUivaLent to wEighting all the primARy-lEvel studies to An eQual DEGrEe. SO WhETheR oNE wiSHEs to or not, when peRforming a mEtA-AnAlysis one iS ForCeD, in prinCiple, to WeighT The primAry-level sTudies, and ThE remAINinG question tHen is simPly how arbITrary ONe'S methOd oF weighTiNg iS. AssiGning eQUal WeighTs regaRdLess of MethoDoLogical qUality is maximally arbitrAry. The Use of qATS to differEntIAllY weight prImarY-level studIes Is aN atteMpt TO miniMize SUcH arBItrarInesS. second, as aRGuEd iN §2 ABoVe, one must acCOUNt fOr finE-grAIned meThodOlogical features iN Order to guarantEe thAT One AvoIDs poTeNtial defeating ProPeRTIes of eviDeNce, and QATs cAn help wiTh THis.
 the strength of the evide nce genera ted f rom  th os e st udie s. One might a g reewith the view that the re is  n o  uni q ue ly be st QAT, bu t bete mp ted  t o  t hinktha t thisis due onl y t othe fact tha t  t he quality  of  a study dep end s on p ar tic u larit ies  of t he con t ext (e .g. the p ar t icular kind of s tu dy i n question and th e  f o rm of the hypo thesis  b e in g tes ted  by that s tu dy).D ifferen t  Q A T s  mi g ht, according  to this th o ugh t, beop tim a lly su itedto dif ferent cont exts . While t his la t ter poi n t is no  doubt  tr ue- abov e  I  n ote dt hat so meQ ATs  are des ig ne d for  ass e s s i ng p art icul ar ki nds of studie s,ando the rs ar e des igne dfor a ssessi ng st ud ies in particul ar d omains of  me di cin e- it do e s notexp lai n the l ow inte r -to ol r e li ability of QATs. T ha t is  16 beca use, a s  a bo v e, the l ow  in ter- t o ol re liab i li ty of QA Ts isd em on strated  i n narr ow lyspe cifie d  con texts.  Moreove r, th e  research grou p s that design QA T s  u s uall y c laim (expli citl y ) th at t h ei r Q A Ts ar e mea nt to be applicable to agi ven st udy d esign (usuall y RCTs) in a l most any  dom a in of medical res earch . In short ,  QATs ar e int ended to  apply to a  broad r ang e o f c ont e x ts , but regardl e s s, t he  empiri cal  demons tra tio nsofth eir low i nter-too lre li ab ili ty ar e  almostal way scon strai n ed toa sin glepa rt i cul ar cont e xt . Desp it ethei r w id espre ad a n d g rowinguse, amon g m e dica lsc ientist s there is so me  debate ab ou t w hether o r not QA Ts ought to be employed at all(se e, fo r ex ample, He rbi son et  al .  (2006 )). Th eir l ow  in t e r-rat e r  a ndin ter-tool r e l iab ility  m ight  sugges t that resistancet o t heir use is w arr ante d .  T her e  a r e t hr e e r e a sons, however,that justi fy th e continui n g i mp rovemen t and a pplic a tion of  QATs toassessing  t he q u a lit y of medic al evide nce. Firs t , whe n  p erfor min g a me ta -an alysi s, a d e cis ion t o notus e an i nstru me nt to di fferentially weight the  quali ty of  th e primary -le v elstudies i s eq uivalent t o w eig hting  al l  theprim a ry -le v el st udie s  to an eq u al  de g r ee . So whethe r o newishe s t o  or no t, w hen performing am eta-analysis o ne i s for ced ,  inpr inciple, to we igh tt h e primar y- level studi es, andth e  rema iningquesti on then i ss implyhowarb itrary on e's  m e thod of  w ei g htingis.As signin g equa l  wei g h ts regardless of  meth o d ologi c alquali ty  is max i mall y arbitrar y. The useof QAT s to  diff erentia ll y weig htpr imary-leve l  studiesis an  attemp tto m ini mize s ucha r bitra rine ss . S econd, as a rg u ed  i n  §2  abo ve, o ne  mus t account for fine -gr a ined me th odo l o gicalf ea t u res in ord erto gu a r antee that onea vo i ds po tentia l defe ating p r ope rt ies ofevi d e nce, andQATs canh elp  w iththis.
 the_strength of_the evidence generated from_those studies._One_might agree_with_the view that_there is no_uniquely best QAT, but_be tempted to_think_that this is due only to the fact that the quality of a study_depends_on particularities_of_the_context (e.g. the particular kind_of study in question and_the form_of the hypothesis being tested by that study)._Different_QATs might, according_to this thought, be optimally suited to different contexts._While this latter point is no_doubt true-above I_noted_that_some QATs are designed_for assessing particular kinds of studies,_and others are designed for assessing_studies in particular domains of medicine-it does_not explain the low inter-tool reliability_of QATs. That is 16_because, as_above, the low inter-tool reliability_of QATs is_demonstrated in_narrowly specified contexts._Moreover, the research groups that design_QATs usually claim_(explicitly) that their QATs are meant_to_be applicable to_a_given_study design_(usually RCTs) in_almost_any domain_of_medical research. In short, QATs are_intended_to apply to a broad range of_contexts, but regardless, the_empirical_demonstrations of their low_inter-tool reliability are almost always_constrained to a single particular context._Despite their_widespread and_growing use, among medical scientists there is some debate about whether_or not QATs ought to be_employed at all (see,_for example,_Herbison_et al. (2006))._Their_low inter-rater_and inter-tool reliability might suggest that resistance_to their_use is warranted. There are three_reasons, however, that justify_the_continuing improvement and application of QATs_to assessing the quality of medical_evidence. First, when performing a_meta-analysis,_a_decision to not use an_instrument to differentially weight the quality_of the primary-level_studies is equivalent to weighting all the_primary-level_studies to an equal degree. So_whether_one wishes to or not, when_performing_a_meta-analysis one is forced, in_principle, to weight the primary-level studies,_and the remaining question then is simply how arbitrary_one's method of_weighting is. Assigning equal weights_regardless_of_methodological quality is maximally arbitrary. The use of QATs to_differentially weight_primary-level studies is_an attempt to minimize such arbitrariness. Second, as argued in_§2 above, one must account for fine-grained_methodological features in order to guarantee that one avoids potential defeating_properties of evidence, and QATs can help with_this.