High-dimensional Ising model selection using ℓ1{\ell_1}-regularized logistic regression

We consider the problem of estimating the graph associated with a binary Ising Markov random field. We describe a method based on $\ell_1$-regularized logistic regression, in which the neighborhood of any given node is estimated by performing logistic regression subject to an $\ell_1$-constraint. The method is analyzed under high-dimensional scaling in which both the number of nodes $p$ and maximum neighborhood size $d$ are allowed to grow as a function of the number of observations $n$. Our main results provide sufficient conditions on the triple $(n,p,d)$ and the model parameters for the method to succeed in consistently estimating the neighborhood of every node in the graph simultaneously. With coherence conditions imposed on the population Fisher information matrix, we prove that consistent neighborhood selection can be obtained for sample sizes $n=\Omega(d^3\log p)$ with exponentially decaying error. When these same conditions are imposed directly on the sample matrices, we show that a reduced sample size of $n=\Omega(d^2\log p)$ suffices for the method to estimate neighborhoods consistently. Although this paper focuses on the binary graphical models, we indicate how a generalization of the method of the paper would apply to general discrete Markov random fields.Comment: Published in at http://dx.doi.org/10.1214/09-AOS691 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Development and validation of an instrument to measure user perceived service quality of mHealth

The role of service quality in fostering the growth of mHealth services has gained much attention in the academic and practitioner communities. However, empirical research in this area has been beset by inadequate conceptualization and the lack of a validated scale. This study addresses these limitations by theoretically conceptualizing and empirically validating a multidimensional service quality scale in the mHealth context. The findings show that mHealth service quality is a hierarchical, multidimensional, and reflective construct, which consists of three primary dimensions and eight subdimensions. The results also confirm that the mHealth service quality scale is more effective at predicting satisfaction and continuance in a nomological network

Modeling Quality Dynamics in IT Services Management

The increasing importance of information technology (IT) services in the global economy prompts IS researchers to focus on service quality dynamics to capture the critical interaction between human behavior and IT. The purpose of this study is to develop and validate a user perceived IT service quality model for mHealth using a cross-disciplinary approach. The conceptual model is rooted in the traditional cognition (service quality) – affective (satisfaction)– conation (continuance intentions) chain but explicitly identifies three primary dimensions (i.e., system quality, interaction quality and outcome quality) and eight subdimensions (system reliability, system efficiency, system privacy, responsiveness, assurance, empathy, utilitarian benefits and hedonic benefits) of IT service quality in mHealth. The findings of the study show that IT service quality is the third-order, reflective, hierarchical construct with strong positive effects on satisfaction and continuance intentions in a nomological network

AN EVALUATION OF PLS BASED COMPLEX MODELS: THE ROLES OF POWER ANALYSIS, PREDICTIVE RELEVANCE AND GOF INDEX

Structural equation modeling (SEM) is an important tool to estimate a network of causal relationships linking two or morecomplex concepts. The PLS approach to SEM, also known as component based SEM, is becoming more prominent forestimating large complex models due to its soft modeling assumptions. This ‘soft modeling’ refers to the greater flexibility ofPLS technique in developing and validating the complex models. However, to establish rigor in such complex modeling, thisstudy highlights the critical roles of power analysis, predictive relevance and GoF index. The findings of the study show thatpower analysis is essential to establish conjectures based on IT artifacts, predictive relevance is vital to measure how wellobserved values are reproduced by the model and finally, GoF index is crucial for assessing the global validity of a complexmodel

User Perceived Service Quality of mHealth Services in Developing Countries

Health challenges present arguably the most significant barrier to sustainable global development. The introduction of ICT in healthcare, especially the application of mobile communications, has created the potential to transform healthcare delivery by making it more accessible, affordable and effective across the developing world. However, there is growing concerns about the quality of such services with regard to the robustness of the service delivery platform, knowledge and competence of the provider, privacy and security of information and above all, their effects on satisfaction, future use intentions and quality of life. The aim of this paper is to explore, analyze and critically assess the use of existing service quality theories in the light of evolving and ubiquitous healthcare services and their underlying technologies. The conceptual model of the study identifies that there are three primary quality dimensions (platform quality, interaction quality and outcome quality) and ten subdimensions (System reliability, system efficiency, system availability, system adaptability, system privacy, assurance, responsivness, empathy, functional benefits and emotinal benefits) which play a vital role in capturing users’ overall perceptions of mobile health services. Finally, the study identifies future research directions and highlights the managerial implications in the context of developing countries

GO NATURAL, SAY NO TO CHEMICALS - A SYSTEMATIC REVIEW ON EFFECTIVENESS OF GREEN TEA EXTRACT CONTAINING FORMULATIONS ON DENTAL CARIES

Objective: In recent years, the side effects encountered with the use of chemicals has led to the search for safe anticariogenic alternatives. Green tea is one such naturally occurring alternative which possesses anticariogenic activity through a direct bactericidal effect against cariogenic microorganisms. Therefore, the objective of this systematic review was to analyze the existing literature on the effectiveness of green tea extract containing formulations on dental caries. Methods: The databases of PubMed, Cochrane, Science Direct, Metapress, and Google Scholar were searched up to July 2015 for the related topic. References of the selected articles and relevant reviews were searched for any missed publications. Results: The systematic search revealed a total of 437 publications which were scrutinized based on eligibility criteria. Six publications fulfilled the criteria and 431 publications were excluded from the review. Out of six studies, three studies reported a statistically significant difference in favor of green tea while two studies showed no statistically significant difference between the groups. One study reported no statistically significant difference between the two groups; however, the reduction observed in chlorhexidine (control group) was slightly greater than green tea. Conclusion: With the available evidence, it can be concluded that green tea extract containing formulations are effective in reducing cariogenic microflora and caries increment

Implementing a participatory model of micro health insurance among rural poor with evidence from Nepal

This paper reports on two voluntary, contributory, contextualised, community-based health insurance (CBHI) schemes, launched in Dhading and Banke (Nepal) in 2011. The implementation followed a four-stage process: initiating (baseline survey), involving (awareness generation and engaging community in benefit-package-design), launch (enrolment and training of selected community members) and post-launch (viable claims ratio, settled within satisfactory time, sustainable affiliation). Both schemes were successful on four key parameters: effective planning; affiliation (grew from 0 to ∼10,000) and renewals (>65 per cent); claims ratio (∼50 per cent); and promptness of claim settlement (∼23 days). This model succeeded in implementing CBHI with zero premium subsidies or subsidised health-care costs. The successful operation relied in large part on the fact that members trust that they can enforce this contract. Considerable insurance education and capacity development is necessary before the launch of the CBHI, and for sustainable operations as well as for scaling

What factors affect voluntary uptake of community-based health insurance schemes in low- and middle-income countries? A systematic review and meta-analysis

Introduction: This research article reports on factors influencing initial voluntary uptake of community-based health insurance (CBHI) schemes in low- and middle-income countries (LMIC), and renewal decisions. Methods: Following PRISMA protocol, we conducted a comprehensive search of academic and gray literature, including academic databases in social science, economics and medical sciences (e.g., Econlit, Global health, Medline, Proquest) and other electronic resources (e.g., Eldis and Google scholar). Search strategies were developed using the thesaurus or index terms (e.g., MeSH) specific to the databases, combined with free text terms related to CBHI or health insurance. Searches were conducted from May 2013 to November 2013 in English, French, German, and Spanish. From the initial search yield of 15,770 hits, 54 relevant studies were retained for analysis of factors influencing enrolment and renewal decisions. The quantitative synthesis (informed by meta-analysis) and the qualitative analysis (informed by thematic synthesis) were compared to gain insight for an overall synthesis of findings/statements. Results: Meta-analysis suggests that enrolments in CBHI were positively associated with household income, education and age of the household head (HHH), household size, female-headed household, married HHH and chronic illness episodes in the household. The thematic synthesis suggests the following factors as enablers for enrolment: (a) knowledge and understanding of insurance and CBHI, (b) quality of healthcare, (c) trust in scheme management. Factors found to be barriers to enrolment include: (a) inappropriate benefits package, (b) cultural beliefs, (c) affordability, (d) distance to healthcare facility, (e) lack of adequate legal and policy frameworks to support CBHI, and (f) stringent rules of some CBHI schemes. HHH education, household size and trust in the scheme management were positively associated with member renewal decisions. Other motivators were: (a) knowledge and understanding of insurance and CBHI, (b) healthcare quality, (c) trust in scheme management, and (d) receipt of an insurance payout the previous year. The barriers to renewal decisions were: (a) stringent rules of some CBHI schemes, (b) inadequate legal and policy frameworks to support CBHI and (c) inappropriate benefits package. Conclusion and Policy Implications: The demand-side factors positively affecting enrolment in CBHI include education, age, female household heads, and the socioeconomic status of households. Moreover, when individuals understand how their CBHI functions they are more likely to enroll and when people have a positive claims experience, they are more likely to renew. A higher prevalence of chronic conditions or the perception that healthcare is of good quality and nearby act as factors enhancing enrolment. The perception that services are distant or deficient leads to lower enrolments. The second insight is that trust in the scheme enables enrolment. Thirdly, clarity about the legal or policy framework acts as a factor influencing enrolments. This is significant, as it points to hitherto unpublished evidence that governments can effectively broaden their outreach to grassroots groups that are excluded from social protection by formulating supportive regulatory and policy provisions even if they cannot fund such schemes in full, by leveraging people's willingness to exercise voluntary and contributory enrolment in a community-based health insurance