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Queen Margaret University

UniversityEdinburgh, United Kingdom

Research output, citation impact, and the most-cited recent papers from Queen Margaret University (United Kingdom). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
5.6K
Citations
196.3K
h-index
161
i10-index
3.3K
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Top-cited papers from Queen Margaret University

Saturation in qualitative research: exploring its conceptualization and operationalization
Benjamin Saunders, Julius Sim, Tom Kingstone, Shula Baker +4 more
2017· Quality & Quantity11.4Kdoi:10.1007/s11135-017-0574-8

Saturation has attained widespread acceptance as a methodological principle in qualitative research. It is commonly taken to indicate that, on the basis of the data that have been collected or analysed hitherto, further data collection and/or analysis are unnecessary. However, there appears to be uncertainty as to how saturation should be conceptualized, and inconsistencies in its use. In this paper, we look to clarify the nature, purposes and uses of saturation, and in doing so add to theoretical debate on the role of saturation across different methodologies. We identify four distinct approaches to saturation, which differ in terms of the extent to which an inductive or a deductive logic is adopted, and the relative emphasis on data collection, data analysis, and theorizing. We explore the purposes saturation might serve in relation to these different approaches, and the implications for how and when saturation will be sought. In examining these issues, we highlight the uncertain logic underlying saturation-as essentially a predictive statement about the unobserved based on the observed, a judgement that, we argue, results in equivocation, and may in part explain the confusion surrounding its use. We conclude that saturation should be operationalized in a way that is consistent with the research question(s), and the theoretical position and analytic framework adopted, but also that there should be some limit to its scope, so as not to risk saturation losing its coherence and potency if its conceptualization and uses are stretched too widely.

Understanding Integration: A Conceptual Framework
Alastair Ager, Adam J. Strang
2008· Journal of Refugee Studies2.3Kdoi:10.1093/jrs/fen016

Integration has become both a key policy objective related to the resettlement of refugees and other migrants, and a matter of significant public discussion. Coherent policy development and productive public debate are, however, both threatened by the fact that the concept of integration is used with widely differing meanings. Based on review of attempted definitions of the term, related literature and primary fieldwork in settings of refugee settlement in the UK, the paper identifies elements central to perceptions of what constitutes ‘successful’ integration. Key domains of integration are proposed related to four overall themes: achievement and access across the sectors of employment, housing, education and health; assumptions and practice regarding citizenship and rights; processes of social connection within and between groups within the community; and structural barriers to such connection related to language, culture and the local environment. A framework linking these domains is presented as a tool to foster debate and definition regarding normative conceptions of integration in resettlement settings.

Organisational change management: A critical review
Rune Todnem By
2005· Journal of Change Management1.2Kdoi:10.1080/14697010500359250

It can be argued that the successful management of change is crucial to any organisation in order to survive and succeed in the present highly competitive and continuously evolving business environment. However, theories and approaches to change management currently available to academics and practitioners are often contradictory, mostly lacking empirical evidence and supported by unchallenged hypotheses concerning the nature of contemporary organisational change management. The purpose of this article is, therefore, to provide a critical review of some of the main theories and approaches to organisational change management as an important first step towards constructing a new framework for managing change. The article concludes with recommendations for further research.

Antimicrobial properties of plant essential oils and essences against five important food-borne pathogens
Smith-Palmer, Stewart, Fyfe
1998· Letters in Applied Microbiology1.0Kdoi:10.1046/j.1472-765x.1998.00303.x

The antimicrobial properties of 21 plant essential oils and two essences were investigated against five important food-borne pathogens, Campylobacter jejuni, Salmonella enteritidis, Escherichia coli, Staphylococcus aureus and Listeria monocytogenes. The oils of bay, cinnamon, clove and thyme were the most inhibitory, each having a bacteriostatic concentration of 0.075% or less against all five pathogens. In general, Gram-positive bacteria were more sensitive to inhibition by plant essential oils than the Gram-negative bacteria. Campylobacter jejuni was the most resistant of the bacteria investigated to plant essential oils, with only the oils of bay and thyme having a bacteriocidal concentration of less than 1%. At 35 degrees C, L. monocytogenes was extremely sensitive to the oil of nutmeg. A concentration of less than 0.01% was bacteriostatic and 0.05% was bacteriocidal, but when the temperature was reduced to 4 degrees, the bacteriostatic concentration was increased to 0.5% and the bacteriocidal concentration to greater than 1%.

Older Adults Perceptions of Technology and Barriers to Interacting with Tablet Computers: A Focus Group Study
Eleftheria Vaportzis, Maria Giatsi Clausen, Alan J. Gow
2017· Frontiers in Psychology895doi:10.3389/fpsyg.2017.01687

BACKGROUND: New technologies provide opportunities for the delivery of broad, flexible interventions with older adults. Focus groups were conducted to: (1) understand older adults' familiarity with, and barriers to, interacting with new technologies and tablets; and (2) utilize user-engagement in refining an intervention protocol. METHODS: Eighteen older adults (65-76 years old; 83.3% female) who were novice tablet users participated in discussions about their perceptions of and barriers to interacting with tablets. We conducted three separate focus groups and used a generic qualitative design applying thematic analysis to analyse the data. The focus groups explored attitudes toward tablets and technology in general. We also explored the perceived advantages and disadvantages of using tablets, familiarity with, and barriers to interacting with tablets. In two of the focus groups, participants had previous computing experience (e.g., desktop), while in the other, participants had no previous computing experience. None of the participants had any previous experience with tablet computers. RESULTS: The themes that emerged were related to barriers (i.e., lack of instructions and guidance, lack of knowledge and confidence, health-related barriers, cost); disadvantages and concerns (i.e., too much and too complex technology, feelings of inadequacy, and comparison with younger generations, lack of social interaction and communication, negative features of tablets); advantages (i.e., positive features of tablets, accessing information, willingness to adopt technology); and skepticism about using tablets and technology in general. After brief exposure to tablets, participants emphasized the likelihood of using a tablet in the future. CONCLUSIONS: Our findings suggest that most of our participants were eager to adopt new technology and willing to learn using a tablet. However, they voiced apprehension about lack of, or lack of clarity in, instructions and support. Understanding older adults' perceptions of technology is important to assist with introducing it to this population and maximize the potential of technology to facilitate independent living.

Geographic Imbalances in Doctor Supply and Policy Responses
Tomoko Ono, Michael Schoenstein, James Buchan
2014· OECD health working papers828doi:10.1787/5jz5sq5ls1wl-en

Doctors are distributed unequally across different regions in virtually all OECD countries, and this causes concern about how to continue to ensure access to health services everywhere. In particular access to services in rural regions is the focus of attention of policymakers, although in some countries, poor urban and sub-urban regions pose a challenge as well. Despite numerous efforts this mal-distribution of physician supply persists. This working paper first examines the drivers of the location choice of physicians, and second, it examines policy responses in a number of OECD countries...

What is balance?
A Pollock, Brian Durward, Philip Rowe, John P. Paul
2000· Clinical Rehabilitation760doi:10.1191/0269215500cr342oa

Balance is a term frequently used by health professionals working in a wide variety of clinical specialities. There is no universally accepted definition of human balance, or related terms. This article identifies mechanical definitions of balance and introduces clinical definitions of balance and postural control. Postural control is defined as the act of maintaining, achieving or restoring a state of balance during any posture or activity. Postural control strategies may be either predictive or reactive, and may involve either a fixed-support or a change-in-support response. Clinical tests of balance assess different components of balance ability. Health professionals should select clinical assessments based on a sound knowledge and understanding of the classification of balance and postural control strategies.

Spasticity: Clinical perceptions, neurological realities and meaningful measurement
Anand Pandyan, M Gregorič, MP Barnes, Duncan Wood +4 more
2004· Disability and Rehabilitation748doi:10.1080/09638280400014576

Abstract not available

Can sample size in qualitative research be determined a priori?
Julius Sim, Benjamin Saunders, Jackie Waterfield, Tom Kingstone
2018· International Journal of Social Research Methodology691doi:10.1080/13645579.2018.1454643

There has been considerable recent interest in methods of determining sample size for qualitative research a priori, rather than through an adaptive approach such as saturation. Extending previous literature in this area, we identify four distinct approaches to determining sample size in this way: rules of thumb, conceptual models, numerical guidelines derived from empirical studies, and statistical formulae. Through critical discussion of these approaches, we argue that each embodies one or more questionable philosophical or methodological assumptions, namely: a naïve realist ontology; a focus on themes as enumerable ‘instances’, rather than in more conceptual terms; an incompatibility with an inductive approach to analysis; inappropriate statistical assumptions in the use of formulae; and an unwarranted assumption of generality across qualitative methods. We conclude that, whilst meeting certain practical demands, determining qualitative sample size a priori is an inherently problematic approach, especially in more interpretive models of qualitative research.

How to do (or not to do) … Designing a discrete choice experiment for application in a low-income country
Lindsay Mangham‐Jefferies, Kara Hanson, Barbara McPake
2008· Health Policy and Planning649doi:10.1093/heapol/czn047

Understanding the preferences of patients and health professionals is useful for health policy and planning. Discrete choice experiments (DCEs) are a quantitative technique for eliciting preferences that can be used in the absence of revealed preference data. The method involves asking individuals to state their preference over hypothetical alternative scenarios, goods or services. Each alternative is described by several attributes and the responses are used to determine whether preferences are significantly influenced by the attributes and also their relative importance. DCEs are widely used in high-income contexts and are increasingly being applied in low- and middle-income countries to consider a range of policy concerns. This paper aims to provide an introduction to DCEs for policy-makers and researchers with little knowledge of the technique. We outline the stages involved in undertaking a DCE, with an emphasis on the design considerations applicable in a low-income setting.

Social Factors and Recovery from Mental Health Difficulties: A Review of the Evidence
Jerry Tew, Shulamit Ramon, Mike Slade, Victoria Bird +2 more
2011· The British Journal of Social Work615doi:10.1093/bjsw/bcr076

Although there is now increasing evidence as to the role played by social factors in contributing to the onset of mental health difficulties, there has been little systematic examination of the role that social factors can play in enabling (or impeding) recovery. This paper provides a review of the emerging international literature in this area, and is linked to a wider conceptual review undertaken as part of a major project researching recovery practice in the UK. Research findings are explored in detail in relation to three areas that had been identified by the wider review as central to recovery: empowerment and control over one's life; connectedness (including both inter-personal relationships and social inclusion); and rebuilding positive identities (often within the context of stigma and discrimination). Out of this emerges a clearer picture of the importance of particular social factors, which starts to define a more broad-based and proactive agenda for mental health social work—with an emphasis not just on working with individuals, but also on engaging with families and communities. However, there is a need for further research and development work in order to determine how to intervene most effectively in order to influence specific social factors.

Physical rehabilitation approaches for the recovery of function and mobility following stroke
Alex Todhunter‐Brown, Gillian Baer, Pauline Campbell, Pei Ling Choo +4 more
2014· Cochrane Database of Systematic Reviews581doi:10.1002/14651858.cd001920.pub3

BACKGROUND: Various approaches to physical rehabilitation may be used after stroke, and considerable controversy and debate surround the effectiveness of relative approaches. Some physiotherapists base their treatments on a single approach; others use a mixture of components from several different approaches. OBJECTIVES: To determine whether physical rehabilitation approaches are effective in recovery of function and mobility in people with stroke, and to assess if any one physical rehabilitation approach is more effective than any other approach.For the previous versions of this review, the objective was to explore the effect of 'physiotherapy treatment approaches' based on historical classifications of orthopaedic, neurophysiological or motor learning principles, or on a mixture of these treatment principles. For this update of the review, the objective was to explore the effects of approaches that incorporate individual treatment components, categorised as functional task training, musculoskeletal intervention (active), musculoskeletal intervention (passive), neurophysiological intervention, cardiopulmonary intervention, assistive device or modality.In addition, we sought to explore the impact of time after stroke, geographical location of the study, dose of the intervention, provider of the intervention and treatment components included within an intervention. SEARCH METHODS: We searched the Cochrane Stroke Group Trials Register (last searched December 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 12, 2012), MEDLINE (1966 to December 2012), EMBASE (1980 to December 2012), AMED (1985 to December 2012) and CINAHL (1982 to December 2012). We searched reference lists and contacted experts and researchers who have an interest in stroke rehabilitation. SELECTION CRITERIA: Randomised controlled trials (RCTs) of physical rehabilitation approaches aimed at promoting the recovery of function or mobility in adult participants with a clinical diagnosis of stroke. Outcomes included measures of independence in activities of daily living (ADL), motor function, balance, gait velocity and length of stay. We included trials comparing physical rehabilitation approaches versus no treatment, usual care or attention control and those comparing different physical rehabilitation approaches. DATA COLLECTION AND ANALYSIS: Two review authors independently categorised identified trials according to the selection criteria, documented their methodological quality and extracted the data. MAIN RESULTS: We included a total of 96 studies (10,401 participants) in this review. More than half of the studies (50/96) were carried out in China. Generally the studies were heterogeneous, and many were poorly reported.Physical rehabilitation was found to have a beneficial effect, as compared with no treatment, on functional recovery after stroke (27 studies, 3423 participants; standardised mean difference (SMD) 0.78, 95% confidence interval (CI) 0.58 to 0.97, for Independence in ADL scales), and this effect was noted to persist beyond the length of the intervention period (nine studies, 540 participants; SMD 0.58, 95% CI 0.11 to 1.04). Subgroup analysis revealed a significant difference based on dose of intervention (P value < 0.0001, for independence in ADL), indicating that a dose of 30 to 60 minutes per day delivered five to seven days per week is effective. This evidence principally arises from studies carried out in China. Subgroup analyses also suggest significant benefit associated with a shorter time since stroke (P value 0.003, for independence in ADL).We found physical rehabilitation to be more effective than usual care or attention control in improving motor function (12 studies, 887 participants; SMD 0.37, 95% CI 0.20 to 0.55), balance (five studies, 246 participants; SMD 0.31, 95% CI 0.05 to 0.56) and gait velocity (14 studies, 1126 participants; SMD 0.46, 95% CI 0.32 to 0.60). Subgroup analysis demonstrated a significant difference based on dose of intervention (P value 0.02 for motor function), indicating that a dose of 30 to 60 minutes delivered five to seven days a week provides significant benefit. Subgroup analyses also suggest significant benefit associated with a shorter time since stroke (P value 0.05, for independence in ADL).No one physical rehabilitation approach was more (or less) effective than any other approach in improving independence in ADL (eight studies, 491 participants; test for subgroup differences: P value 0.71) or motor function (nine studies, 546 participants; test for subgroup differences: P value 0.41). These findings are supported by subgroup analyses carried out for comparisons of intervention versus no treatment or usual care, which identified no significant effects of different treatment components or categories of interventions. AUTHORS' CONCLUSIONS: Physical rehabilitation, comprising a selection of components from different approaches, is effective for recovery of function and mobility after stroke. Evidence related to dose of physical therapy is limited by substantial heterogeneity and does not support robust conclusions. No one approach to physical rehabilitation is any more (or less) effective in promoting recovery of function and mobility after stroke. Therefore, evidence indicates that physical rehabilitation should not be limited to compartmentalised, named approaches, but rather should comprise clearly defined, well-described, evidenced-based physical treatments, regardless of historical or philosophical origin.

Objective measurement of physical activity and sedentary behaviour: review with new data
J.J. Reilly, V. Penpraze, Jane Hislop, Gwyneth Davies +2 more
2008· Archives of Disease in Childhood567doi:10.1136/adc.2007.133272

Objective methods are being used increasingly for the quantification of the amount of physical activity, intensity of physical activity and amount of sedentary behaviour in children. The accelerometer is currently the objective method of choice. In this review we address the advantages of objective measurement compared with more traditional subjective methods, notably the avoidance of bias, greater confidence in the amount of activity and sedentary behaviour measured, and improved ability to relate variation in physical activity and sedentary behaviour to variation in health outcomes. We also consider unresolved practical issues in paediatric accelerometry by critically reviewing the existing evidence and by providing new evidence.

Focus group methodology: some ethical challenges
Julius Sim, Jackie Waterfield
2019· Quality & Quantity477doi:10.1007/s11135-019-00914-5

Focus group methodology generates distinct ethical challenges that do not correspond fully to those raised by one-to-one interviews. This paper explores, in both conceptual and practical terms, three key issues: consent; confidentiality and anonymity; and risk of harm. The principal challenge in obtaining consent lies in giving a clear account of what will take place in the group, owing to unpredictability of the discussion and interaction that will occur. As consent can be seen in terms of creating appropriate expectations in the participant, this may therefore be hard to achieve. Moreover, it is less straightforward for the participant to revoke consent than in one-to-one interviews. Confidentiality and anonymity are potentially problematic because of the researcher’s limited control over what participants may subsequently communicate outside the group. If the group discussion encourages over-disclosure by some participants, this problem becomes more acute. Harm in a focus group may arise from the discussion of sensitive topics, and this may be amplified by the public nature of the discussion. A balance should be struck between avoiding or closing down potentially distressing discussion and silencing the voices of certain participants to whom such discussion may be important or beneficial. As a means of addressing the above issues, we outline some strategies that can be adopted in the consent process, in a preliminary briefing session, during moderation of the focus group, and in a subsequent debriefing, and suggest that these strategies can be employed synergistically so as to reinforce each other.

What determines patient satisfaction with surgery? A prospective cohort study of 4709 patients following total joint replacement
David Hamilton, Julie Lane, Paul Gaston, James T. Patton +3 more
2013· BMJ Open473doi:10.1136/bmjopen-2012-002525

OBJECTIVES: To investigate the factors which influence patient satisfaction with surgical services and to explore the relationship between overall satisfaction, satisfaction with specific facets of outcome and measured clinical outcomes (patient reported outcome measures (PROMs)). DESIGN: Prospective cohort study. SETTING: Single National Health Service (NHS) teaching hospital. PARTICIPANTS: 4709 individuals undergoing primary lower limb joint replacement over a 4-year period (January 2006-December 2010). MAIN OUTCOME MEASURES: Overall patient satisfaction, clinical outcomes as measured by PROMs (Oxford Hip or Knee Score, SF-12), satisfaction with five specific aspects of surgical outcome, attitudes towards further surgery, length of hospital stay. RESULTS: Overall patient satisfaction was predicted by: (1) meeting preoperative expectations (OR 2.62 (95% CI 2.24 to 3.07)), (2) satisfaction with pain relief (2.40 (2.00 to 2.87)), (3) satisfaction with the hospital experience (1.7 (1.45 to 1.91)), (4) 12 months (1.08 (1.05 to 1.10)) and (5) preoperative (0.95 (0.93 to 0.97)) Oxford scores. These five factors contributed to a model able to correctly predict 97% of the variation in overall patient satisfaction response. The factors having greatest effect were the degree to which patient expectations were met and satisfaction with pain relief; the Oxford scores carried little weight in the algorithm. Various factors previously reported to influence clinical outcomes such as age, gender, comorbidities and length of postoperative hospital stay did not help explain variation in overall patient satisfaction. CONCLUSIONS: Three factors broadly determine the patient's overall satisfaction following lower limb joint arthroplasty; meeting preoperative expectations, achieving satisfactory pain relief, and a satisfactory hospital experience. Pain relief and expectations are managed by clinical teams; however, a fractured access to surgical services impacts on the patient's hospital experience which may reduce overall satisfaction. In the absence of complications, how we deliver healthcare may be of key importance along with the specifics of what we deliver, which has clear implications for units providing surgical services.

Refugee Integration: Emerging Trends and Remaining Agendas
Adam J. Strang, Alastair Ager
2010· Journal of Refugee Studies441doi:10.1093/jrs/feq046

This paper uses the foundation of the conceptual framework proposed by Ager and Strang (2004a, 2008) to reflect on the focus and findings of papers in this special issue on refugee integration and other recent work. Arguing that ‘mid-level theory’ of the sort presented in the framework provides a strong basis for structuring academic debate and dialogue with practitioners and policymakers, we identify four key issues that although of some current interest warrant further attention. First, we consider recent evidence from Europe and elsewhere on how prevailing notions of nationhood and citizenship determine understandings of integration, and argue that this powerfully shapes the social space available to refugees with regard to ‘belonging’. Second, we note the wide adoption of concepts of social capital in framing components of social connection in the context of integration, but suggest greater attention is paid to the manner in which bonds, bridges and links establish forms of reciprocity and trust in social relations. Third, we examine the notion that integration is a ‘two way’ process, and suggest how this might be expanded to embrace the multiplicity and fluidity of social meaning and identity. Fourth, we reflect on Hobfoll’s (1998) work on ‘resource acquisition spirals’ as a basis for effectively conceptualizing the dynamic interplay between factors mapped by the framework in shaping trajectories of integration.

Prosody in autism spectrum disorders: a critical review
Joanne McCann, Sue Peppé
2003· International Journal of Language & Communication Disorders432doi:10.1080/1368282031000154204

BACKGROUND: Many individuals with autism spectrum disorders present with unusual or odd-sounding prosody. Despite this widely noted observation, prosodic ability in autism spectrum disorders is often perceived as an under-researched area. AIMS: This review seeks to establish whether there is a prosodic disorder in autism, what generalizations can be made about its various manifestations and whether these manifestations vary according to the diagnosis. A literature review was carried out to establish what areas of prosody in autism spectrum disorders have been researched to date, what the findings have been and to determine what areas are yet to be researched. MAIN CONTRIBUTION: It is shown that prosody in autism spectrum disorders is an under-researched area and that where research has been undertaken, findings often conflict. The findings of these conflicting studies are compared and recommendations are made for areas of future research. CONCLUSIONS: Research in this area has covered mostly prosodic expression, although some more recent studies cover comprehension, processing and the relationship of receptive prosodic ability to theory of mind. Findings conflict and methodology varies greatly.

Solving nursing shortages: a common priority
James Buchan, Linda H. Aiken
2008· Journal of Clinical Nursing386doi:10.1111/j.1365-2702.2008.02636.x

AIMS AND OBJECTIVES: This paper provides a context for this special edition. It highlights the scale of the challenge of nursing shortages, but also makes the point that there is a policy agenda that provides workable solutions. RESULTS: An overview of nurse:population ratios in different countries and regions of the world, highlighting considerable variations, with Africa and South East Asia having the lowest average ratios. The paper argues that the 'shortage' of nurses is not necessarily a shortage of individuals with nursing qualifications, it is a shortage of nurses willing to work in the present conditions. The causes of shortages are multi-faceted, and there is no single global measure of their extent and nature, there is growing evidence of the impact of relatively low staffing levels on health care delivery and outcomes. The main causes of nursing shortages are highlighted: inadequate workforce planning and allocation mechanisms, resource constrained undersupply of new staff, poor recruitment, retention and 'return' policies, and ineffective use of available nursing resources through inappropriate skill mix and utilisation, poor incentive structures and inadequate career support. CONCLUSIONS: What now faces policy makers in Japan, Europe and other developed countries is a policy agenda with a core of common themes. First, themes related to addressing supply side issues: getting, keeping and keeping in touch with relatively scarce nurses. Second, themes related to dealing with demand side challenges. The paper concludes that the main challenge for policy makers is to develop a co-ordinated package of policies that provide a long term and sustainable solution. RELEVANCE TO CLINICAL PRACTICE: This paper highlights the impact that nursing shortages has on clinical practice and in health service delivery. It outlines scope for addressing shortage problems and therefore for providing a more positive staffing environment in which clinical practice can be delivered.

Modeling Developmental Language Difficulties From School Entry Into Adulthood: Literacy, Mental Health, and Employment Outcomes
James Law, Robert Rush, Ingrid Schoon, Samantha Parsons
2009· Journal of Speech Language and Hearing Research385doi:10.1044/1092-4388(2009/08-0142)

PURPOSE: Understanding the long-term outcomes of developmental language difficulties is key to knowing what significance to attach to them. To date, most prognostic studies have tended to be clinical rather than population-based, which necessarily affects the interpretation. This study sought to address this issue using data from a U.K. birth cohort of 17,196 children, following them from school entry to adulthood, examining literacy, mental health, and employment at 34 years of age. The study compared groups with specific language impairment (SLI), nonspecific language impairment (N-SLI), and typically developing language (TL). METHOD: Secondary data analysis of the imputed 5-year and 34-year data was carried using multivariate logistic regressions. RESULTS: The results show strong associations for demographic and biological risk for both impairment groups. The associations are consistent for the N-SLI group but rather more mixed for the SLI group. CONCLUSIONS: The data indicate that both SLI and N-SLI represent significant risk factors for all the outcomes identified. There is a strong case for the identification of these children and the development of appropriate interventions. The results are discussed in terms of the measures used and the implications for practice.

Rasch fit statistics and sample size considerations for polytomous data
Adam B. Smith, Robert Rush, Lesley Fallowfield, Galina Velikova +1 more
2008· BMC Medical Research Methodology377doi:10.1186/1471-2288-8-33

BACKGROUND: Previous research on educational data has demonstrated that Rasch fit statistics (mean squares and t-statistics) are highly susceptible to sample size variation for dichotomously scored rating data, although little is known about this relationship for polytomous data. These statistics help inform researchers about how well items fit to a unidimensional latent trait, and are an important adjunct to modern psychometrics. Given the increasing use of Rasch models in health research the purpose of this study was therefore to explore the relationship between fit statistics and sample size for polytomous data. METHODS: Data were collated from a heterogeneous sample of cancer patients (n = 4072) who had completed both the Patient Health Questionnaire - 9 and the Hospital Anxiety and Depression Scale. Ten samples were drawn with replacement for each of eight sample sizes (n = 25 to n = 3200). The Rating and Partial Credit Models were applied and the mean square and t-fit statistics (infit/outfit) derived for each model. RESULTS: The results demonstrated that t-statistics were highly sensitive to sample size, whereas mean square statistics remained relatively stable for polytomous data. CONCLUSION: It was concluded that mean square statistics were relatively independent of sample size for polytomous data and that misfit to the model could be identified using published recommended ranges.