Estimation of the mean quality-adjusted survival using a multistate model for the sojourn times

In clinical trials, it may be of interest taking into account physical and emotional well-being in addition to survival when comparing treatments. Quality-adjusted survival time has the advantage of incorporating information about both survival time and quality-of-life. In this paper, we discuss the estimation of the expected value of the quality-adjusted survival, based on multistate models for the sojourn times in health states. Semiparametric and parametric (with exponential distribution) approaches are considered. A simulation study is presented to evaluate the performance of the proposed estimator and the jackknife resampling method is used to compute bias and variance of the estimator.     

Bayesian assessment of times to diagnosis in breast cancer screening

Breast cancer is one of the diseases with the most profound impact on health in developed countries and mammography is the most popular method for detecting breast cancer at a very early stage. This paper focuses on the waiting period from a positive mammogram until a confirmatory diagnosis is carried out in hospital. Generalized linear mixed models are used to perform the statistical analysis, always within the Bayesian reasoning. Markov chain Monte Carlo algorithms are applied for estimation by simulating the posterior distribution of the parameters and hyperparameters of the model through the free software WinBUGS.     

A proposal for handling ordinal categorical variables in co-inertia analysis

This paper is about the problem of the treatment of ordinal qualitative variables in co-inertia analysis. In the literature, there are different proposals based on the application of known statistical techniques to quantify ordinal variables. Here we propose to use a new procedure for the coding considering the empirical distributions of the variables involved in the analysis. We present an application to a real dataset, comparing the results obtained with the different kinds of quantification.     

Developing green innovation performance by fostering of organizational knowledge and coopetitive relations

This study explores the links between knowledge base, relationship learning, and green innovation performance within a coopetitive framework. We posit that green innovation is directly influenced by a broad and deep knowledge base. We also hypothesize that the knowledge base–green innovation performance link is positively mediated by relationship learning (indirect effect). These hypotheses were empirically tested using consistent partial least squares path modeling. A sample of 112 firms from the Spanish automotive components manufacturing sector was used. The mediating effect of relationship learning on the knowledge base–green innovation performance link was observed to be positive and significant. Therefore, managers should build strong relations with stakeholders to assimilate, transfer, and adapt new knowledge and thus enhance green innovation performance.     

Innovation through tradition in the Italian coffee industry: an analysis of customers’ perceptions

The extant literature reveals how firms may innovate by exploiting past competencies and resources, hence proposing innovation through tradition as an emerging strategy to compete. Previous research largely demonstrates that the effectiveness of an innovation strategy is strictly dependent on the capability of firms to communicate the right message to their customers. Therefore, leveraging products’ attributes becomes fundamental to strategically position their commercial offerings in the minds of the target audience. Nevertheless, despite the well-known relevance of this issue, scant attention has been devoted to investigate the product attributes that consumer’s associate with innovation and with tradition when companies deploy strategies based on “innovation through tradition”. Accordingly, our study aims at covering this gap, by empirically analyzing the consumers’ perception of innovation and tradition in the Italian coffee industry through a positioning analysis. Our research allowed us to identify two sets of product attributes that consumers associate with innovation and tradition. The results show that in many cases the innovation-related and tradition-related attributes are strongly negatively correlated, but in some case the correlation is weak or close to zero. These attributes reveal that in some cases innovation and tradition can be combined in the perception of consumers, rather than representing opposite constructs. This result suggests that companies can effectively communicate the strategy of innovation through tradition to the consumers’ minds, but this must be done by choosing the right attributes.     

The Balanced Worth: A Procedure to Evaluate Performance in Terms of Ordered Attributes

There are many problems in the social sciences that refer to the evaluation of the relative performance of some populations when their members’ achievements are described by a distribution of outcomes over a set of ordered categories. A new method for the evaluation of this type of problems is presented here. That method, called balanced worth, offers a cardinal, complete and transitive evaluation that is based on the likelihood of getting better results. The evaluation of each society is based on the probability of obtaining better results with respect to the others. The balanced worth is a refinement of “the worth” (Herrero and Villar in PLoS ONE 8(12):e84784, 2013.  https://doi.org/10.1371/journal.pone.0084784) that overcomes its excessive sensitivity to the differences, due to the presence of ties. We also discuss how this method can be applied for the case of heterogeneous populations and show how it can be applied in different contexts. An empirical example, regarding life satisfaction in Spain is used to illustrate the working of this method.     

Urbanization homogenizes the interactions of plant-frugivore bird networks

Urban Ecosystems - Anthropogenic activities are the main cause of habitat loss and fragmentation, which directly affects biodiversity. Disruption in landscape connectivity among populations may...