Applying the ICF linking rules to compare population-based data from different sources: an exemplary analysis of tools used to collect information on disability.

BACKGROUND: Data on disability are regularly collected by different institutions or ministries using specific tools for different purposes, for instance to estimate the prevalence of disability or eligibility of specific populations for social benefits. The interoperability of disability data collected in countries is essential for policy making and to monitor the implementation of the Convention on the Rights of Persons with Disabilities. The first objective of this paper is to map and compare tools that collect data on disability for different purposes, more specifically the Brazilian National Health Survey and the Brazilian Functioning Index to the World Health Organization (WHO) and the World Bank Model Disability Survey (MDS), currently recommended as a standard tool for disability measurement. The second objective is to demonstrate the usefulness and value of the International Classification of Functioning, Disability and Health Linking Rules to map and compare population-based surveys and other content-related tools collecting data on disability, even when these have already been developed based on the International Classification of Functioning, Disability and Health. METHODS: Disability information collected with the three different tools was mapped and compared using the International Classification of Functioning, Disability and Health Linking Rules. RESULTS: Although the disability module in the Brazilian National Health Survey is fundamentally different from the MDS, the mapping disclosed that several modules of the Brazilian National Health Survey already cover many aspects necessary to estimate prevalence and understand disability as currently recommended by the WHO and the World Bank. The Brazilian Functioning Index and the MDS are both based on the International Classification of Functioning, Disability and Health and are very similar in the approach and content of their questions on functioning. Specific information on environmental factors is essential to identify needs and barriers, as well as to devise procedures to reduce injustice and inequalities. This information is still not targeted broadly enough in both the Brazilian National Health Survey and the Brazilian Functioning Index. CONCLUSIONS: Overall, this mapping exercise showed that applying the International Classification of Functioning, Disability and Health linking rules to population-based data coming from different sources provides researchers and stakeholders involved in decision-making with standardized and straightforward information about overlaps and gaps. Implications for Rehabilitation Data on functioning and disability regularly collected with different purposes and by different institutions or ministries within a country can be compared using the International Classification of Functioning, Disability and Health as a reference framework and the International Classification of Functioning, Disability and Health linking rules. The recently published refinements of the International Classification of Functioning, Disability and Health Linking Rules go beyond the sole linking to International Classification of Functioning, Disability and Health categories and provide standardized procedures to document the perspective of linked questions or the categorization of response options. They are therefore useful to compared tools that have been developed based on the International Classification of Functioning, Disability and Health. The current disability module of the Brazilian Health Survey needs a revision to be suitable to collect data on disability that is Convention on the Rights of Persons with Disabilities conform and guarantees interoperability with disability data from other sources in Brazil, especially from disability assessment for social benefits and implementation of policies.

The Impact of Missing Values and Single Imputation upon Rasch Analysis Outcomes: A Simulation Study.

Imputation becomes common practice through availability of easy-to-use algorithms and software. This study aims to determine if different imputation strategies are robust to the extent and type of missingness, local item dependencies (LID), differential item functioning (DIF), and misfit when doing a Rasch analysis. Four samples were simulated and represented a sample with good metric properties, a sample with LID, a sample with DIF, and a sample with LID and DIF. Missing values were generated with increasing proportion and were either missing at random or completely at random. Four imputation techniques were applied before Rasch analysis and deviation of the results and the quality of fit compared. Imputation strategies showed good performance with less than 15% of missingness. The analysis with missing values performed best in recovering statistical estimates. The best strategy, when doing a Rasch analysis, is the analysis with missing values. If for some reason imputation is necessary, we recommend using the expectation-maximization algorithm.

All metrics are equal, but some metrics are more equal than others: A systematic search and review on the use of the term 'metric'.

OBJECTIVE: To examine the use of the term 'metric' in health and social sciences' literature, focusing on the interval scale implication of the term in Modern Test Theory (MTT). MATERIALS AND METHODS: A systematic search and review on MTT studies including 'metric' or 'interval scale' was performed in the health and social sciences literature. The search was restricted to 2001-2005 and 2011-2015. A Text Mining algorithm was employed to operationalize the eligibility criteria and to explore the uses of 'metric'. The paradigm of each included article (Rasch Measurement Theory (RMT), Item Response Theory (IRT) or both), as well as its type (Theoretical, Methodological, Teaching, Application, Miscellaneous) were determined. An inductive thematic analysis on the first three types was performed. RESULTS: 70.6% of the 1337 included articles were allocated to RMT, and 68.4% were application papers. Among the number of uses of 'metric', it was predominantly a synonym of 'scale'; as adjective, it referred to measurement or quantification. Three incompatible themes 'only RMT/all MTT/no MTT models can provide interval measures' were identified, but 'interval scale' was considerably more mentioned in RMT than in IRT. CONCLUSION: 'Metric' is used in many different ways, and there is no consensus on which MTT metric has interval scale properties. Nevertheless, when using the term 'metric', the authors should specify the level of the metric being used (ordinal, ordered, interval, ratio), and justify why according to them the metric is at that level.

Self-Efficacy and Pressure Ulcer Prevention After Spinal Cord Injury-Results From a Nationwide Community Survey in Switzerland (SwiSCI).

BACKGROUND: Pressure ulcers (PUs) are a common and severe health condition in persons with spinal cord injury (SCI). Skin-care strategies for PU prevention are usually provided during initial rehabilitation. However, individuals with SCI often do not perform these strategies continuously, especially after discharge. The influence of psychological factors such as general self-efficacy (GSE) on the performance of PU prevention behavior has not yet been sufficiently explored. OBJECTIVE: To investigate whether persons with greater levels of GSE are more likely to perform skin-care strategies for PU prevention regularly. DESIGN: Nationwide cross-sectional survey within the Swiss Spinal Cord Injury Cohort Study. SETTING: Community setting, data collection between 2011 and 2013. PARTICIPANTS: A total of 456 subjects with a traumatic or nontraumatic SCI living in Switzerland. METHODS: Associations between GSE and PU prevention behavior were analyzed by multivariate proportional odds regression models, including potential sociodemographic, lesion-related, and lifestyle-related confounders without and with interaction terms between GSE and potential effect modifiers. MAIN OUTCOME MEASUREMENTS: Self-efficacy was assessed by the GSE scale comprising 10 items. PU preventive behavior was operationalized using 5 items of an adapted version of the Spinal Cord Injury Lifestyle scale. Both measurements were components of a self-administered questionnaire. RESULTS: Based on the regression model without interaction terms, GSE levels were not associated with skin-care PU prevention. After we included interaction terms, the final model showed statistically significant associations between GSE and 3 skin-care items with odds ratios ranging from 1.09 to 1.17 (all P < .001). The slightly positive effect of GSE on PU prevention behavior was restricted to persons who sustained their SCI at a younger age. CONCLUSIONS: GSE was generally not associated with skin-care PU prevention behavior among persons with SCI in this study. In further research, it might be of interest to assess SCI-specific concepts of self-efficacy. LEVEL OF EVIDENCE: III.