Abstract Completeafterfullpaperhasbeenreviewed. Introduction The concept of health literacy is relatively new, originating roughly 50 years ago (Simonds, 1974). Over the past 20 years, however, it has started to garner considerable traction in research, policy, and practise due to its potential benefits to both individual and public health (Nutbeam, 2000; Berkman et al., 2011; Benzinger et al., 2009). In short, health literacy is one’s ability to meet the demands of modern society in order to maintain and promotehealth(Kickbusch&Maag,2008). Originally, health literacy was predominantly concerned with the ability to read and write medical information, focusing mostly on applying general literacy skills to a health context. Recent developments, however, have resulted in the widening of the concept to consider the rangeofcompetenciesrequiredtounderstand,communicate,actuponhealthsituations throughout life(Peerson&Saunders,2009).Nutbeam(2000)statedthatalthoughfunctional health literacy is crucial for patients to understand health illness and treatments, focusing solely on the functional side of health literacy misses much of the deeper meaning and purposes of health literacy for people. As such, Nutbeam (2000) proposed that there are three ‘types’ of health literacy: functional, interactive, andcriticalhealthliteracy.Functional health literacy is concerned with the basic reading and writing skills required to find health information and apply health knowledge to a range of prescribed activities and everyday situations. Interactive health literacy skills are more advanced cognitive social and literacy skills which can be used to participate actively in everyday situations, extract health information and derive meaning from different forms of health communication, and apply this to changing circumstances. Critical health literacy is often considered the most advanced and is concerned with the ability to critically question health-related information in personal situations and to use this information to exert control over health situations. Given this typology, health literacy can be considered a set of individual skills that can be developed to provide one with greater autonomy and empowerment over their health decision-making. Given the ever-growing impact of an individual’s social and physical environment on their health, as well as the increasing complexities of health care systems, the need for one to develop the health literacy skills to make healthy decisions and to navigate the health system is at an all-time high (Schaeffer et al., 2020). Despite this, although population level health literacy data is limited, one extensive study has shown health literacy levels are low across many countries in Europe, with 12% of the participants studied showing insufficient levels of health literacy and 47% had limited health literacy levels (Sørensen et al., 2015). Low levels of health literacy have been shown to have many negative consequences, including increased likelihood of adopting poor behaviours, a higher risk of disease, decreased self-care, and reduced capacity to manage with illness and over- and misuse (extensive use) of health care systems (Berkman et al., 2011; Bröder et al., 2018). The promotion of health literacy is therefore an important task of public health, with some stating that addressing health literacy on anationalandinternationalshouldbeaprioritytoreducing the prevalence of chronic diseases, early mortality and increasing health costs (Pleasant et al., 2015). The WHO has recognised health literacy as a critical determinant of health and committed to develop, implement, and monitor national and local strategiesfor strengtheninghealthliteracyinallpopulationsandalleducationalsettings(WHO,2017). As health literacy is a relativelynewconcept,whichappearstobeconstantlyevolving,there is aneedtoreviewitskeyelementsanddimensions.ResearchcarriedoutbySørensenetal., (2012) systematically reviewed existingdefinitionsandconceptsofhealthliteracywithinthe international literature in order to develop a comprehensive and integrated definition and conceptual model. In the process, the authors identified a list of central dimensions and overarching clusters for each dimension to sit within. Although this was a seminal piece of research, which wascrucialindevelopingtheconceptualisationandunderstandingofhealth literacy, research is neededtoupdatethisworkanddetailanyfurthergrowthoftheconcept anditsconstituentdimensionoverthepast12years. Thus, this umbrella review aims to build on the methods and findings of Sørensen et al., (2012) to provide a comprehensive update on the key dimensions of health literacy according to the international literature. The findings of this review areintendedtoprovide clarity and support in operationalising the complex concept of health literacy, as well as informingfuturehealthliteracyresearch,evidence-basedpractiseandpolicy. Methods This umbrella review was registered a priori with PROSPERO (ID: CRD42024535025) and followed the Preferred Reporting ItemsforSystematicReviewsandMeta-Analyses(PRISMA) umbrellareviewmethodologicalguidelines(Aromatarisetal.,2015). StudyDesign Given the existence of multiple studies which have previously aimed to define, conceptualise, or review definitions and conceptualisations of health literacy, instead of reviewing primary papers, an umbrella review (Aromataris et al., 2015), also known as a systematic review of reviews (Smith et al., 2011), was conducted. Umbrella reviews, which integrate the findings of previously conducted reviews on the same or similar topic, are a relatively new form of evidence synthesis. The comparison and contrasting of findings of review studies allows for the evaluation of the consistency of research findings, the compilation of greater volumes of evidence and the discovery of insights adding value beyond restating previous findings (Hasanpoor et al., 2019). This type of review is particularly useful when multiple reviews already exist on a topic (as is the case within this topic area), yet there is still a lack of a consensus around a specific issue. By implementing an umbrella review in this instance, allows for the comparison and contrasting of health literacy definitions and conceptualisation in ordertodevelopagreaterunderstandingofthe concept and to identify the most common health literacy dimensions. Although the systematic review by Sørensen et al., (2012) reviewed definitions and conceptualmodelsof health literacy and identified specific dimensions of health literacy, it is 12 years since this research was published with numerous systematic reviews being conducted since. Given health literacy is such a fast-growing and ever evolving concept, this review will aim toprovide a comprehensive and contemporary understanding of the concept that can inform thedevelopmentoffuturehealthinterventionsandpolicies. SearchStrategy Three electronic databases were searched—PubMed, Web of Science and Scopus—to identify relevant evidence. ‘English’ and ‘peer reviewed’filtersweremarkedonallsearches. The search strategy was developed using Boolean operators (AND/OR), incorporating the relevant terms (Appendix X). Specifically, 17 keywords (definition, model, concept, dimension, framework, conceptual framework, theory, analysis, qualitative, quantitative, competence, skill, "public health", communication, information, functional, critical) were combined (using the Boolean operator and) with the search terms "health literacy". The search was limited to publications after 2012 (post the seminal publication of Sorenson et al., 2012). Furthermore, the search strategy and choice of databases were alsoinformedby Sørensen et al., (2012). The search was conducted between July and August 2023. All records were exported to Covidence managing software for screening and all duplicates were removed. Two reviewers independently assessed the eligibility of the studies. Following title and abstract screening, full-text copies of potentially relevant studies were obtained andscreenedforfull-textinclusion.Inthecaseofdisagreement,athirdauthorwas contactedfordiscussionuntilconsensuswasreached. StudySelectionCriteria The final review only included systematic review studies that (i) assigned primary focus to the definition of health literacy in the main body of the article, (ii) were published in an academic journal, (iii) were written in English language, and (vi) were published after 2012. We formulated no restrictions for the target population of the review. For more detail see TableX. TableX:PICOTable Include Exclude Population Allpopulations Intervention Studieswillbeincludedif Papersnotcoveringthedefinition,or theyreportonthe associationsofhealthliteracy;(ii) definitionofhealth papersthatusedhealthliteracyinthe literacy title,keywordsorabstract,butmade noreferencetohealthliteracyinthe fullbodyoftext;(iii)studieswherethe definitionwasnotthemainfocusof thereview Context “healthliteracy”or “healtheducation”or “healthknowledge”or “healthinformation”or “healthunderstanding”Outcomes Studieswillbeincludedif theyreportonthe definitionofhealth literacy Study SystematicReview Studiespublishedinaforeign design/publication Peerreviewedjournal language characteristics articlespublishedin Notpublishedinapeerreviewed English journal Duplicatepublication Fulltextarticleswerenotavailable, Bookchapters Casestudies Protocolpapers? Primarystudies Conferenceabstracts Researchframework Analysisandsynthesisofresults The methods adopted toanalyseandsynthesisethefindingsofthisreviewwerebuiltonthe work ofSørensenetal.,(2012)andfollowedasimilarprocesstothatofBröderetal.,(2019). Specifically, all studies included within the review were qualitatively assessed and synthesised using a deductive content analysis (see figure X). Firstly, eligible studies were screened for common definitions and conceptualisations of health literacy. Followingthis,a deductive analysis of the dimensions of each definition and/or conceptualisation of health literacy identified within this study was carried out using the six clusters of health literacy and theindividualdimensionspreviouslyidentifiedbySørensenetal.,(2012).Thesebroader clusters of health literacy developed by Sørensen et al., (2012) included (1) competence, skills, abilities; (2) actions; (3) information and resources; (4) objective; (5) context; and (6) time, with each individual cluster containing a range of individual dimensions relating to health literacy (see Table X) Therefore, the dimensions of health literacy, which were included within the definitions and/or conceptualisation identified within the studies reviewed as part of this study, were mapped to the clusters and individual dimensions previously developed by Sørensen et al., (2012). Additional dimensions, which were not previously identified by Sørensen et al., (2012), but were contained within the definitions and/or conceptualisations of health literacy reviewed within this study, were added to the relevant wider cluster yieldedbySørensenetal.,(2012).Similardimensions(orsynonymsof dimensions) were then grouped together withinthecluster.SeeFigureXforabreakdownof this process. In the case of disagreement of whether a new dimension was, a third author was contacted for discussion regarding which clusters a specific dimension until consensus wasreached. The aim of the deductive content analysis was to develop a comprehensive map of health literacy dimensions, each aligning to a specific cluster previously identified by Sørensen et al., (2012). For a full breakdown of each cluster and the accompanying dimensionsforeach includedstudy,pleaseseeTableX.FigureX:Theprocessofthedeductivecontentanalysis Results Figure x below details the search and screening process. The literature search yielded 1291 publications; after removing 507 duplicates, 784 publications were subsequently screened. Of these publications, 757 were excluded based on title and abstract because they did not fulfil one or more of the inclusion criteria. The remaining 27publicationswereretrievedfor full-text review. A total of 18 failed to meet the inclusion criteria, leaving nine remaining studies. The main reasons for excluding full texts were that health literacy was not defined withinthepublicationandthestudyoutcomesirrelevanttotheresearchquestion. FigureX: PRISMAchartofsystematicsearchprocess.TableXbelowdisplaysthehealthliteracydimensionspreviouslyidentifiedbySørensenet al.,(2012)andmapswhichofthesedimensionswereusedtodefineorconceptualisehealth literacywithintheninereviewpapersincludedaspartofthisstudy.Furthermore,itdetails therangeofadditionaldimensionsincludedwithinthestudiescarriedoutsincetheseminal workofSørensenetal.,carriedoutin2012.Assuch,thetablehighlightsdimensionswhich havebeencommonlyassociatedwithhealthliteracy,aswellastherangeofsynonymsused todescribethesedimensions.Thesynonymshavebeengroupedwithinthetable. This review, which builds on the work of Sørensen et al., (2012), further highlights health literacy as a multidimensional concept. Although Sørensen et al., (2012) identified a huge array of dimensions previously, this review demonstrated the developing nature of the concept of health literacy, with many additional dimensions added over the last decade. Based on thisreview,itappearsthathealthliteracyencompasses,amongothers,one’sskills, competencies, knowledge, and motivation to carry out a wide range of actions throughout the life course in order to promote and maintain healthwithinthehealthcaresettingandin everydaylife.HLdimensions Malloy-Weir Bröderetal., Flearyetal., Huhtaetal., Kasgarietal., Liuetal., Trumanetal., Urstadetal., Muscatetal., (Sorensenet etal.,(2016) (2017) (2018) (2018) (2020) (2020) (2020) (2022) (2022) al.,2012) Competence/Skills/Abilities Skills Y Y Y Y Y Possessionof Y Y Y Y Y requisite skills/Constellati onof skills/Wide rangeofskills Personalskills Y Y Cognitiveskills Y Y Y Y Y Y Socialskills Y Y Y Y Y Y Theability Y Y Y Y Y Y Y Thecapacity Y Y Y Y Y Y Y The Y Y competencies Theknowledge Y Y Y Y Y Y Motivation Y Y Y Y Y Y Y Comprehension Y Y Y Communication Y Y Y Y Y Y Thestrategies Y Attitude Y Y Y Y Healthpractices Y Y Y Confidence Y Y Self-efficacy Y Y Beliefs Y Y Self-directednes Y s Productivity Y Interests Y Self-awareness Y Citizenship Y(Environmental) Y Consciousness Intention Y Scientific Y knowledge Education Y Personaland Y economic abilities Action/Agency Tounderstand Y Y Y Y Y Y Y Y Tocomprehend Y Y Y Toprocess Y Y Y Y Y Y Y Tointerpret Y Touse Y Y Y Y Y Y Y Y Toapply Y Y Y Y Y Y Y Toemploy Y Toact Y Y Y Toperform Y Y Y Y Y Y Y basicreading andnumerical tasks Toperform Y arithmetic operations Toread Y Y Toseekout Y Y Y Y Y Togainaccess Y Y Y Y Y Y Y Y Tofind Y Y Toobtain Y Y Y Y Y Y Y Toacquire Y Y Toidentify YTofilter Y Y Toappraise Y Y Y Y Y Y Y Tothink Y critically Toanalyse Y Y Toassess Y Y Toevaluate Y Y Y Y Y Y Todiscernthe Y qualityof information To Y Y Y Y Y communicate Toarticulate Y Toembraceor disregard actions Toderive Y meaning Tomakesound Y Y decisions/to make health-related decisions Todecision Y make Totake Y Y responsibility Topertain interactions Tointeract Y Y Y Toattain Y capacity, comprehension and communicationToencompass Y Y Tointegrate Y Toconstruct Y Y Toorganise Y Y Tocreatemedia Y messages Tonavigate Y Y Y Toenable Y Y Tofunction Y Tolisten Y Y Torecognise Y Toengage Y Todevise Y appropriate search strategies Tosynthesise Y Y Tomanage Y Y Toimplement Y Toproblem Y solve Tonegotiate Y Toaccepta Y condition/ learntolive withadisease Tocope Y Y Toself-regulate Y Y Toprovide Y information Toset,initiate, Y manageand evaluatehealth goalsInformation Information Y Y Y Y Y Y Y Health Y Y Y Y Y Y Y information Information Y Y Y Y relatingto health Basichealth Y Y Y Y Y Y information Healthdata Y Information Y relatingtoa healthylifestyle Healthrelevant Y terms,factsand principles Medicaland Y Y healthcare terminology, information, andinstructions (medications, labels, appointments, forms,medical settingsand systems) Health-related Y Y print-material Information presentedin graphicalformHealth Y informationin written,spoken ordigitalform Differentforms Y Y of communication Health Y Y information fromelectronic sources Informational Y and communicative technology Online Y information Concepts Y Y Y Services Y Y Y Y Y Y Y Y Advertisingand Y othermedia messages Culturally Y relevant/ specificand age-appropriate information Objective/Purposes Promoteand Y Y Y Y Y Y Y maintaingood health Topromote Y Y Y Y healthToenhance Y health Toimprove Y Y Y health Tofunctionin Y Y Y thehealthcare environment Tomake Y Y Y Y Y Y Y Y appropriate healthdecisions Tomake Y Y Y Y Y informed choices Tomake Y Y Y appropriate healthandcare decisions Toformsound Y Y Y Y Y Y Y judgments Acritical Y Y empowerment strategyto increase people’scontrol overtheir health Tobetter Y controlhealth Toempower Y Y thisgrouptobe moreengaged, more productive,and healthierTomanage Y one’shealth environment Increasequality Y Y Y Y Y Y oflife Toengagein demandsof differenthealth contexts Tomakepublic healthdecisions thatbenefitthe community Toinfluence Y Y Y individualsand society Toimproveor Y achieve complete well-being Toachieve Y complete biopsychosocial health Tochangetheir Y health behavioursor livingconditions Toaddressor Y Y solveahealth issue Toaccomplish health-related objectives Tobuild Y Y individualandCompetences,SkillsandAbilities The wide range of skills associated with health literacy was highlighted within the review. Although many have stated vaguely that ahealthliteratepersonrequirespersonalskillsora constellation of skills (Malloy-Weir et al., 2016; Huhta et al., 2018; Kasagri et al.,2020; Truman et al., 2020;Urstadetal.,2022),othershavepositedthatonerequiresmorespecific cognitive and social skills. Examples of such, which are contained within thereview,include the ability to comprehend (Bröder et al., 2017; Liu et al., 2020; Truman et al., 2020) and communicate (Malloy-Weir et al., 2016; Bröder et al., 2017; Kasgari et al., 2020; Liu et al., 2020; Truman et al., 2020; Urstad et al., 2022) appropriately, as well as someone’s level of knowledge (Bröder et al., 2017; Huhta et al., 2018; Kasgari et al., 2020; Liu et al., 2020; Truman et al., 2020; Urstad et al., 2022). Furthermore, the review underscored the psychological influence on health literacy. Although the importance of motivation was comprehensively reiterated (Malloy-Weir etal.,2016;Bröderetal.,2017;Flearyetal.,2018; Huhta et al., 2018; Kasagri et al.,2020; Truman et al., 2020; Urstad et al.,2022),thespecific influence of an individual’s self-efficacy (Kasgari et al., 2020; Liu et al., 2020), attitudes (Bröder et al., 2017; Huhta et al., 2018; Kasgari et al., 2020; Urstad et al., 2022) and beliefs (Huhtaetal.,2018;Urstadetal.,2022)onhealthliteracywasalsostated. Action,Agency This cluster included the widest variety of dimensions, with many being added to the work of Sørensen etal.,(2012)fromthisreview.Theabilitytofind,understand,criticallyappraise, and apply health information was clearly linked with the health literacy of a person, with each of these actions (or synonyms of theseactions)occurringacrossallbutone(Muscatet al., 2022) of the review papers included within this umbrella review. The significance of emotional regulation was also included as a key dimension, including the ability to emotionally self-regulate to the demands of an experience and to cope with health situations or conditions (Bröder et al., 2017; Kasgari et al., 2018; Liu etal.,2020).Although, there has been a move to ensure that health literacy encompasses more than just basic literacy skills, based on the findings of thisreviewitappearsthatsuchskillsarestilldeemed critical to one’s health literacy (Malloy-Weir et al., 2016; Fleary et al., 2018; Huhta et al., 2018;Kasgarietal.,2020;Liuetal.,2020;Trumanetal.,2020;Urstadetal.,2022). Information Although the vast majority of included reviews identified information as being a key dimension to health literacy, how it was phrased varied across the studies. Some opted to just include ‘information’ broadly within their definition or conceptualisation (Malloy-Weir et al., 2016; Fleary et al., 2018; Huhta et al., 2018; Kasgari et al., 2020; Liu et al., 2020; Truman et al., 2020; Urstad et al., 2022), whereas many stated the information should be relating to health and healthservices(Malloy-Weiretal.,2016;Bröderetal.,2017;Flearyet al., 2018; Huhta et al., 2018; Kasgari et al., 2020; Liu et al., 2020; Urstad et al., 2022) or health concepts (Malloy-Weir et al., 2016; Huhta et al., 2018;Liuetal.,2020).Somestudies were more specific, including the importance of being able to deal with medical and healthcare terminology, instructions, and information relating to health systems (Huhta et al., 2018; Kasgari et al., 2020). Additionally, the form of the information also varied, with some stating the importance of one not just being able to deal with health information in written and spoken form, but also emphasised the importance of dealing with digital,electronic, and online forms of information (Fleary et al.,2018;Huhtaetal.,2018;Liuetal., 2020). ObjectivesandPurposes Similarly, this cluster was also wide-reaching, emphasising the important role of health literacy. The overarching purpose of health literacy, based on the included reviews, was to increase quality of life (Malloy-Weir et al., 2016; Bröder et al., 2017; Huhta et al., 2018; Kasgari et al., 2020; Truman et al., 2020; Urstad et al., 2022) and to promote or maintain health (Malloy-Weir et al., 2016; Bröder et al., 2017; Fleary et al., 2018; Huhta et al., 2018; Kasgari et al., 2020; Liu et al., 2020; Truman et al., 2020; Urstad et al., 2022). Other key objectives based on the findings of the review, which potentially contribute to the overarching purpose, included theabilitytounderstandhealthissues,componentsofhealth and how to take action in order to address potential health complications and prevent disease (Bröder et al., 2017; Huhta et al., 2018; Kasgari et al., 2020); the ability to make appropriate and informed healthcare choices, decisionsandjudgements(Malloy-Weiretal., 2016; Bröderetal.,2017;Flearyetal.,2018;Huhtaetal.,2018;Kasagrietal.,2020;Liuetal., 2020; Truman et al., 2020; Urstad et al., 2022); to empower one to take more control over their health (Bröder et al., 2017; Kasgari et al., 2020; Liu et al., 2020); and to have the capacity to function within the healthcare environment (Malloy-Weir etal.,2016;Kasgariet al.,2020;Liuetal.,2020). Context Regarding the context, the healthcare environment appeared to occur most commonly within the review (Fleary etal.,2018;Huhtaetal.,2018;Kasgarietal.,2020;Liuetal.,2020; Truman et al., 2020). This includes, quite generally, health care systems (Liu et al., 2020), settings (Fleary et al., 2018; Liu et al., 2020), and health situations (Huhta et al., 2018). Furthermore, the review suggests that health literacy contexts include a‘varietyofsettings’ (Malloy-Weir et al., 2016; Huhta et al., 2018;Liuetal.,2020),suchaseverydaylifecontexts. For example, in the community, workplace, marketplace, online, during physical and psychosocial activities and within the political arena (Malloy-Weir et al.,2016;Bröderetal., 2017; Huhta et al., 2018; Kasgari et al., 2020; Liu et al., 2020;Trumanetal.,2020;Urstadet al.,2022). Time The concept ofhealthliteracy,basedonthereview’sfindings,isbasedacrossthelifecourse, with some definitions and conceptualisations stating that it evolves over the lifetime (Malloy-Weiretal.,2016;Bröderetal.,2017;Huhtaetal.,2018;Trumanetal.,2020). Discussion This umbrella review has further highlighted the complex and multidimensional nature of the concept of health literacy, whichisinlinewithpreviousliterature(Sorensenetal.,2012; Broder et al., 2018; Huhta et al., 2020). Building on the research of Sorensen et al., (2012), this review has reinforced the wide-reaching nature of health literacy, with a considerable number ofadditionaldimensionsidentified,specificallyinrelationtothecompetences,skills and abilities; action and agency; information; objectives and purposes; and contextelements of the concept. To the best of our knowledge this is the first umbrella review carried out on this topic, providing a broad overview of the concept, and a contemporary updateofthefieldofresearchtodate. Although the findings from this review provide valuable information around the specific skills and actions associated withhealthliteracy,aswellasitskeypurposesandthecontexts it should be considered within, which may be used to inform future policy and practice, it also demonstrates the lack of consensus around the conceptualisation and definition of health literacy. Despite numerous attempts, there appears to be no common definition or conceptual model of health literacy to date, with previous observations suggesting that there may be a lack of understanding around what is regarded as a clear component of health literacy andwhatisaconsequence,anantecedentorjustbroadlyassociatedwiththe concept (Paakkari and Paakkari 2012; Broder et al., 2018). This is evident in the findings of this review. For example, many of the dimensions detailed within the various categories, particularly the ‘competences, skills and abilities’ and the ‘action/agency’ categories, inthis review have been deemed antecedents in previous work (Sorensen et al., 2012 and Broder et al., 2018). This lack of clear definition and conceptualisation may lead to a nebulous concept, whereby the perpetual growth of its dimensions and components lead to further difficulty in applying and measuring the health literacy of an individual. It must be noted, however, that this is a somewhat understandable development given the relatively recent emergence of health literacy as a concept, and its drastic evolution from a basic concept associated with one’s ability to read health related material to a much more complex and diverseconcept,encompassinganarrayofnecessarycompetencestomeetthehealthneeds ofthemodernworld,aswellasfactorsthatmayplayaninfluentialrole. This review not only highlights thecomplexityandpotentialimportanceofhealthliteracyto empower individuals in modern society, but also the sizeable responsibility placed on an individual to develop and maintain adequate health literacy levels. It is clear from the findings theimmensenumberofcompetences,skills,andabilities,aswellastheactionsone may be required to acquire in order navigate health-related situations across a range of contexts in everyday life. Such a skillset, coupledwiththevariousandever-growingnumber of antecedents to being health literate, such asthefoundationalcompetences(e.g.,general literacy skills, individual characteristics) and demographic, psychosocial, and culturalfactors (Sorensen et al., 2012; Mancuso et al., 2008), places a significant focus on the individual to develop their health literacy as anindividualcapability.ThisreiteratesthefindingsofBroder et al., (2018), who also highlighted that although contextual factors were sometimes acknowledged in health literacy definitions and conceptualisations of young people, the majority of the emphasis is placed on the individual developing the health literacy capacities. Such an approach, which places the onusontheindividualtodevelopthehealth literacy skills, fails to consider the range of factors that may be out of one’s control potentiallyactingasbarrierstodoingso. Furthermore, as discussed by Muscat et al., (2020), although it is critical that we consider health literacy as a personal asset (a set of personal skills and knowledge that can be developed and used to navigate health situations), health literacy must also be conceptualised as a risk factor for good health (Nutbeam, 2008). There is often amismatch between the literacy level of health-related materials, educationandinformation,aswellashealthcare services provided,andtheliteracyandhealthliteracylevelsofitsintendedtarget audience (Nutbeam, 2008; Kaphingst etal.,2012;Pleasantetal.,2015).Thiscreatesamajor barrier to one accessing and/or understanding the health information provided, communicating their health care needs, and consequently acting upon the available health care (Paasche-Orlow et al., 2007). Thus, as well as aiming to develop a range of individual health literacy competencies (functional, interactive, and critical health literacy skills), it is crucial that policy makers, health educators and health care service providers aim to mitigate the impacts of low health literacy levels by removing literacy-related barriers and makinghealthinformationmoreaccessible,moreunderstandable,andeasiertoacton. This review, as well as highlighting the difficulty in one developing healthliteracylevelsdue to the vast array of dimensions associated, it also points towards a possible reason for the difficulty in developing appropriate health literacy measurement tools. Early efforts to develop health literacy measurement tools focused predominantly assessing functional health literacy skills, such as reading, writing, and understanding basic health information (e.g. food labels). These include theRapidEstimateofAdultLiteracyinMedicine,theTestof Functional Health Literacy in Adults, and the Newest Vital Sign (Davis et al., 2006; Parker, Baker, Williams, & Nurss, 1995; Weiss et al., 2005). These tools were clearly aimed at developing clinical level health literacy, which was in line the evolutionary stage of the concept of health literacy at the time. Although more recent developments have been made, inlinewiththeevolutionoftheconcept,withregardstohealthliteracymeasurement tools, the majority of these have also been criticised. One major criticism of these tools is the self-report method required to evaluate one’s health literacy (Pleasant, 2014), which may lead to an individual reporting their self-efficacy rather than health literacy, lack of uptake due to distressing situations or distrust in health care professional, and shame in admitting their poor literacy levels (Frisch et al., 2012; Parikhetal.,1996).Asaresult,there has been a unanimous call for health literacy tools, with many stating that the existing measures do not match the current understandingsofhealthliteracy(Pleasant&McKinney, 2011). It must be acknowledged that developing an appropriate health literacy tool concurrently with the rapid evolution and expansion of the concept ofhealthliteracyposes an incredibly difficult, if not impossible, task.Thisreviewhashighlightedthespeedatwhich the concept is growing, with ahugenumberofindividualdimensions,acrossthemajorityof overarching health literacy clusters, being added in just over a decade. In addition,itiswell established that health literacy is very much a context specific concept, which requires context specific measurement tools to appropriately assess one’s healthliteracy(Spillaneet al., 2020; McKenna et al., 2017; Naigaga et al., 2024). With these difficulties in mind, one must consider is it worth changing the angle of attack when it comes to health literacy measurement tools. In an article written by Pleasant et al., (2015), theauthorsrecommend moving away from the deficit model of health literacy, whereby instead of focusing on the negative impacts of low levels of health literacy, there is a move to focusingonthepositive impacts that developing health literacy can have on the health and well-being of an individual, communities, and the world. In line with this, and given the limitations of the existing measurement instruments, it is proposed that instead of attempting to directly measuring health literacy(andallofit’stherelevantdimensions),thisshiftwouldencourage the assessment of specific targeted health indicators (e.g. health behaviours, health outcomes, health knowledge, self-efficacy) in relation to the intensity of exposure to the health literacy interventions, and the extent to which interventionsadheretobestpractisesof health literacy. This shift would provide a more practical and useful approach to measuring the impact ofhealthliteracy-relatededucation,policies,andpractiseandprovide anunderstandingonwherethevalueofhealthliteracy,andspecifichealthliteracystrategies lie. The importance of critical health literacy has been well supported in the literature, with modern health literacy definitions taking on a multidimensional approach. This was supported in this review, as many of the included review studies either included critical health literacy dimensions from the work of Sorensen et al., (2012) or added their own dimension relating tocriticalhealthliteracy(giveexamples).Arecentreviewstudy,however, stated that there is a tendency for research to refer to early definitions of health literacy, which represent a functional understanding of the concept and are often devoid of the critical health literacy element (Huhta et al., 2018). Moreover, it has been shown in a population level study that critical health literacy is typically lowest and most difficult to develop (REF). As detailed by Nutbeam (2000), critical health literacy supports more advanced levels of knowledge and skills that support greater autonomy and personal empowermentinhealth-relateddecision-makingandmanagement. Conclusion Completeafterreview. Supplementarymaterial