Diffusion in small worlds with homophily and social reinforcement: A theoretical model

We introduce homophily in a percolation model of word-of-mouth diffusion in social networks by reorganizing the nodes according to similarity in preferences for adoption of an innovation. Such preferences are described by a “minimum utility requirement” for an agent to adopt. We show that homophily removes the non-linear relation between preferences and diffusion in the standard percolation model with a high diffusion regime (“hit”) and a low diffusion regime (“flop”). Instead, in a model with perfect homophily, the final diffusion scales linearly with individual preferences: all agents who are willing to adopt, do adopt the innovation. We also investigate the combined effect of homophily and social reinforcement in diffusion. Results indicate that social reinforcement renders clustered networks more efficient in terms of diffusion size for network with strong homophily, while the opposite is true for networks without homophily. The simple structure of our model allows to disentangle the effect of social influence, homophily and the network structure on diffusion. However, the controllability of the theoretical structure comes at the expenses of the realism of the model. For this, we discuss possible extensions and empirical applications.     

Adjusting for Time‐Varying Confounding in Survival Analysis

In this paper we illustrate how directly including endogenous time‐varying confounders in the model of the effect of an exposure on a response can lead to bias in discrete time survival analysis. An alternative to this method is Hernán, Brumback, and Robins'(1999) use of sample weights to adjust for endogenous time‐varying confounding. We discuss when this method can be used to provide unbiased estimators, and we illustrate the method by addressing a substantive research question using existing survey data. We also critically examine the robustness of the weighting method to violations of the underlying assumptions via a simulation analysis.     

Life satisfaction,income and personality

We use personality traits to better understand the relationship between income and life satisfaction. Personality traits mediate the effect of income on life satisfaction. The effect of neuroticism, which measures sensitivity to threat and punishment, is strong in both the British Household Panel Survey and the German Socioeconomic Panel. Neuroticism increases the usually observed concavity of the relationship: individuals with a higher neuroticism score enjoy extra income more than those with a lower score if they are poorer, and enjoy extra income less if they are richer. When the interaction between income and neuroticism is introduced, income does not have a significant effect on its own. To interpret the results, we present a simple model based on Prospect Theory, where we assume that: (i) life satisfaction is dependent on the gap between aspired and realized income, and this is modulated by neuroticism and (ii) income increases in aspirations with a slope less than unity, so that the gap between aspired and realized income increases with aspirations. From the estimation of this model we argue that poorer individuals tend to over-shoot in their aspirations, while the rich tend to under-shoot. The estimation of the model also shows a substantial effect of traits on income.     

Dementia Problem Behavior and the Production of Informal Caregiving Services

Informal caregivers of individuals with Alzheimer's disease spend a considerable amount of time providing care. In this paper, we use Grossman's health production and Becker's time allocation models to develop a model of informal care provision to elderly dementia patients. In our model, time inputs produce caregiving services, which provides utility to the caregiver, but reduces leisure. We assume that time is less productive of services on the margin as the disease progresses. In this framework, an increase in patients' disease severity does not necessarily increase informal caregiver time input. The cost of formal care establishes a reservation price for informal caregiving. When the costs of informal caregiving rise above this reservation level, the patient is institutionalized. We test empirically the effect of deterioration in the patients' condition, proxied by both disease severity and dementia problem behavior, on informal caregiving time. We find that dementia-related problem behaviors and functional limitations significantly increase inputs of informal caregiving time. Patients' problem behavior exerts a modifying effect on functional limitations, and patients' comorbidities have no effect on informal caregiving time.     

The impact of WIC on breastfeeding initiation and gestational weight gain: Case study of South Carolina Medicaid mothers

In this study, we estimate the effect of the Special Supplemental Nutrition Program for Women, Infant and Children (WIC) on breastfeeding initiation at hospital discharge and gestational weight gain, by relying on South Carolina birth certificates data for 2004–2013. The unique longitudinal feature of the data allows us to utilize maternal fixed effects to account for non-random selection into WIC. Contrary to the existing evidence, we find that WIC participation does not have a negative effect on breastfeeding initiation. We uncover an important heterogeneity in WIC's effect by race. More specifically, we find that WIC participation is associated with an increase in breastfeeding initiation among black mothers by nearly 7%, with no statistically significant effect among white mothers. We also document a reduction in the likelihood of an inadequate gestational weight gain of nearly 10% among white and black mothers.     

Market hours,household work,child care,and wage rates of partners: an empirical analysis

The aim of this paper is to provide new evidence on the effect of partners’ wages on partners’ allocation of time. Earlier studies concluded that wage rates are an important determinant of partners’ hours of market and non-market work and also that house work may lower married women’s wage rates. However, the bulk of earlier literature in this area failed to account for the endogeneity of wages or the simultaneity of partners’ time allocation choices. Here we take a reduced form approach and specify a ten simultaneous equations model of wage rates, employment and hours of market work, house work and childcare of parents. Non-participants are included in the model. We exploit a rich time use dataset for France to estimate the model. We find that the own wage affects positively own market hours and negatively own house work and childcare hours. The wage of the father has a significantly negative effect on the mother’s market hours while her wage rate has a significantly positive effect on his house work hours.     

Entrepreneurial gain,cultural similarity and transnational entrepreneurship

The aim of this article is to analyse the factors affecting the motivations of immigrant entrepreneurs to generate an entrepreneurial gain (positive impact on home and host countries). We consider that positive reasons for emigrating can increase transnational entrepreneurship and mutual benefits for both societies. To test this hypothesis we present a model using Structural Equation Modelling (SEM). This model explains the relations between motivations, cultural similarities, institutions and transnational linkage potentials. We designed an ad hoc search of Argentinean entrepreneurs established in Spain, both as EU citizens and without legal EU status, using online social networks. We applied an online questionnaire to 214 such entrepreneurs. We conclude that institutional rules (formal and informal) greatly influence the location decisions of firms and immigrant entrepreneurs’ motivations for starting transnational business because they provide the frame for the development of profitable opportunities.     

International Economic Assistance and Migration: The Case of Sub‐Saharan Countries

Development aid is commonly advocated as one of the most effective instruments to reduce international migration. Nevertheless, empirical evidence shows that push factors do not automatically result in massive migrations and that aid policies systematically fail to meet their stated objectives. Recently, several contributions have argued that an increase in sending countries’ wealth may lead to a rise in migration, rather than to a reduction, because it enables people to assume the costs and risks of migrating. However, despite the growing number of studies on this phenomenon, the role played by Official Development Assistance (ODA) has not received attention yet. This paper aims at providing empirical evidence on this specific issue. In particular, we investigate the relation between ODA and international migration rates of sub‐Saharan countries. We argue that ODA may have a positive effect on migration decisions for two reasons. First, ODA improves workers’ ability to cover the costs of migration, by providing new job opportunities and in turn increasing incomes in the recipient country. Second, ODA, which is often associated with development programs in education, communication services, and business opportunities, may also stimulate mobility aspirations of potential migrants. We develop an econometric analysis in order to investigate this hypothesis. Specifically, we perform a three‐stage least square estimation on a sample of 48 sub‐Saharan countries. We build a two‐equation model, so as to allow for endogeneity of ODA, and find that ODA has a positive and statistically significant effect on migration outflows. Thus, as our main contribution, we argue that development aids are not substitute for migration and that the traditional aid policies (such as those of the European Union), aimed at curbing migration by providing international financial aids, might need to be reconsidered.     

What Pediatric Subspecialists Need to Know About Sexual and Reproductive Health: A Review of the American Board of Pediatrics Content Outlines for Subspecialty Certifying Examinations

ABSTRACT

Many adolescents with complex medical conditions regard their subspecialty providers as an important source of clinical information including sexual and reproductive health information related to their medical condition. Thus, training for pediatric subspecialty providers should include clinically relevant sexual and reproductive content. The purpose of this study is to understand what disease-relevant sexual and reproductive health information is currently included in content outlines for each of the available pediatric subspecialty certifying examinations. The American Board of Pediatrics (ABP) offers 17 subspecialty certifying examinations; 13 content outlines are available on the ABP website which defines the body of knowledge to be tested. Each available outline underwent content analysis for sexual and reproductive health information. A team of adolescent medicine physicians identified seven thematic areas including: 1) puberty; 2) sexual behavior and identity; 3) fertility; 4) contraception; 5) sexually transmitted infections; 6) other genital pathology; 7) pregnancy. Across disciplines, learning objectives related to sexual behavior, sexual identity, fertility, contraception and pregnancy were the most limited. However, content related to puberty, sexually transmitted infections and other genital pathology was better represented. Overall, disease-and treatment-specific sexual and reproductive health information was sparse. Most subspecialty content outlines contain very little disease-specific sexual and reproductive health information despite the growing adolescent and young adult population with complex medical conditions in the care of pediatric subspecialists. Further studies are needed to explore if lack of sexual and reproductive information on board exams relates to the knowledge base and skill set of pediatric subspecialists.     

Modellvergleich und Ergebnisinterpretation in Logit- und Probit-Regressionen

In the social sciences logit and probit models are often used multivariate data analysis procedures for binary dependent variables. Both procedures can be thought of as resting on a linear model for an unobserved variable y* from which a nonlinear model for the probability of y?=?1 is derived. We first show that compared to linear models this nonlinearity leads to problems of interpreting results from such analysis. In particular odds ratios (exponentiated logit coefficients) often used in logistic regression are problematic in this respect. Instead we recommend using graphical procedures and reporting (corrected) average marginal effects (AME). Based on a series of Monte-Carlo simulations we next demonstrate that the regression coefficients from logit and probit models should not be compared between nested models. Because model building in the social sciences often employs a stepwise procedure a method allowing valid comparisons of effect sizes between models would be advantageous. Results from our simulation study show that average marginal effects and regression coefficients corrected by a method proposed by Karlson et al. (Sociological Methodology 42, 2012) lead to satisfactory results in many different scenarios. In contrast, y*-standardized coefficients are of limited utility and coefficients from a linear probability model should only be used with normally distributed variables.     

Outcome valence and externality valence framing in public good dilemmas

The aim of this paper is to examine how framing influences people’ s cooperation behavior in social dilemmas. In Experiment 1 we investigated the influence of outcome valence (positive vs. negative outcome) and externality valence (positive vs. negative externality) framing on players’ willingness to cooperate in a repeated public good game. We found a significant interaction effect on first-round cooperation, indicating larger cooperation rates when there is a negative outcome valence and a positive externality on others. Furthermore, this effect remained largely stable when comparing cooperation over all rounds, resulting in 45–63% increased cooperation compared to the other conditions. In Experiment 2 we replicated the effect in an applied vignette study, lending support for the generalizability of this framing effect. Taken together, these findings suggest that public goods provisions may be increased substantially by framing the situation’s outcome valence as negative rather than positive.     

Model Fit in Structural Equation Models with Censored, Ordinal, and Dichotomous Variables: Testing Vanishing Tetrads

Although the methodology for handling ordinal and dichotomous observed variables in structural equation models (SEMs) is developing rapidly, several important issues are unresolved. One of these is the optimal test statistic to apply as a test of overall model fit. We propose a new "vanishing tetrad" test statistic for such models. We build on Bollen's (1990) simultaneous test statistic for testing multiple vanishing tetrads and on Bollen and Ting's (1993) confirmatory tetrad analysis (CTA) for hypothesis testing of model structures. These and other works on vanishing tetrads assume continuous observed variables and do not consider observed categorical variables. In this paper we present a method to test models when some or all of the observed variables are collapsed or categorical versions of underlying continuous variables. The test statistic that we provide is an alternative "overall fit" statistic for SEMs with censored, ordinal, or dichotomous observed variables. Furthermore, the vanishing tetrad test sometimes permits us to compare the fit of some models that are not nested in the traditional likelihood ratio test. We illustrate the new test statistic with examples and a small simulation experiment comparing it with two other tests of model fit for SEMs with ordinal or dichotomous endogenous variables.     

REFORM SUPPORT IN TIMES OF CRISIS: THE ROLE OF FAMILY TIES

We argue that an important determinant of voters' support for economic reform is the strength of family ties. While the “crisis hypothesis” predicts that crises facilitate reform, we show in a political economy model that this relation can break down, and even reverse, when agents take into account the effect of reform on their family members. Applied to southern European countries with strong family ties, the model rationalizes why the extremely high (youth) unemployment following the Great Recession has not led to more substantial labor market reforms. In such countries austerity might block rather than foster additional structural reforms. (JEL D64, D72, J48)     

Complementarity of pensions and training under multiemployer plans

We compare firmoptimizing and institutional models of labor contracts to investigate how different types of pension plans affect employee training. Unlike previous stud-ies, we consider an expanded voice model of training and pension coverage in which worker and union preferences feed back on firm decisions, and we test for this bidi-rectional causality between pensions and training. A standard view is that firms pro-vide pensions to optimize their training costs. However, when pension coverage is treated as endogenous in a twostage least squares regression (the data are merged 1991 CPS samples), pensions have a negative effect on training. In contrast, when the pension is a definedbenefit, multiemployer plan, training and pensions are comple-ments, consistent with both optimizing and institutional models. We are grateful for excellent research assistance from Michael Ash, Bhashkar Mazumder, and Judith Ruha and for suggestions from Dale Belman, David Card, B.J. Lee, David MacPherson, and John Turner.     

Union campaign activities and voter preferences

The impact of campaign activity on voting preferences in union representation elections is investigated using a panel study approach. The context of this study is a four-year, multicampus, university system, in which two faculty unions competed vigorously for representation rights for several years. We propose a multivariate model of individual voting intentions which, we argue, depend on the precampaign expected consequences of collective bargaining, recent changes in institutional conditions, various normative and value constraints, and union campaign activity. Both self-reports of exposure to campaign activity and exogenous measures of campus-specific organizing efforts are used in the analysis. The use of exogenous indicators of campaign activity, which we argue is more appropriate, suggests that campaign activity exerts no appreciable effect on the manner in which individuals vote in such elections. Policy implications of these findings are discussed. The authors are grateful to an anonymous reviewer for comments on an earlier version.     

Health international non-governmental organizations,democracy, and tuberculosis mortality in developing nations: A longitudinal analysis

ABSTRACT

Using data from 1985 to 2005 for 74 developing nations, we conduct a longitudinal cross-national analysis examining the contentions of world polity theorists that health-related international non-governmental organizations (HINGOs) are effective at reducing tuberculosis mortality. We find support for this hypothesis in our models, yet we re-specify our models from a social movements perspective to examine any effects democracy may have on TB mortality. We do this by constructing an interaction term between HINGO concentration and level of democracy. As a result, we find that democracy moderates the effect of HINGOs on TB. Higher concentrations of HINGOs within developing nations are correlated with a larger beneficial effect on tuberculosis mortality in nations with high levels of democracy versus more repressive nations. This suggests that the effectiveness of HINGO programs in fighting TB mortality is contingent on the political opportunity structure within the countries where they operate.     

Trust, child care technology choice and female labor force participation

In this paper we investigate whether trust has an effect on the choice of child care technology and on female labor force participation. Mothers with less trust in others may decide to stay at home with their child instead of working. To do this, we sketch a simple model to show why this effect may be taking place, we measure trust using the European Social Survey and we test its influence on the choice of child care technology. To measure trust, we use the methodology proposed by Spady (Semiparametric methods for the measurement of latent attitudes and the estimation of their behavioural consequences. To measure trust, we use a recent semiparametric item response model. Compared to other measures of trust, using this technique has several advantages: it allows the aggregation of information from several questions and exploits additional information from personal and demographic characteristics. It also imposes very few parametric assumptions. The results show that trust matters for the degree of externalness of the child care technology people choose. It can therefore be a possible explanation for differences in female labor force participation across countries and across sociological groups.     

Comparing public attitudes toward providing for the livelihood of the elderly in two aging societies: Germany and Japan

Using an ordered logit model on representative survey data, we study attitudes about who should provide for the livelihood of the elderly in two aging societies—Germany and Japan. We find that in both countries, those with higher income are more inclined toward the private option, whereas age has the opposite effect. Part-time work status negatively (positively) affects the inclination toward a government-based pension system in Japan (Germany). Other significant influences are the pensioner status of the respondents in Japan and specific left-wing party support in the case of Germans.     

Knowing that you mimic me: the link between mimicry,awareness and liking

Mimicry pays off for a mimicker, and that mimickees are not aware of being influenced by mimicry. In this study, we investigated the link between mimicry, awareness and liking using a 2 (mimicry: yes/no) × 4 (awareness manipulation) experimental design. We found a main effect of mimicry (the confederate was liked more in the mimicry condition) and an interaction between mimicry and awareness. Awareness manipulation had a limited effect on the association between mimicry and liking. Providing participants with little or no information about mimicry (information not including any remarks about its consequences) had an effect on the association between mimicry and liking. However, when participants were informed about the interpersonal consequences of mimicry, mimicry did not influence liking.