Deriving Target Selection Rules from Endogenously Selected Samples

One of the aims of direct marketing in practice is to target the most profitable customers in the database at hand. This selection is often done based on observed behavior in the past. As a consequence, databases arising from the responses to direct mailings are not a random sample from all potential respondents. When not all heterogeneity is observed, part of the target selection rule will be based on the unobserved heterogeneity, so selection is endogenous. Treating an endogenously selected sample as a random sample results in inconsistent parameter estimates, which in general also harms the predictive performance of the model. We develop an adjustment to the likelihood of the model that corrects for the endogenous sample selection. We apply this technique to the selection of mail targets for a charitable organization. In the application we also show that, based on a model for the response rate and the amount donated simultaneously, we can create a target selection rule that maximizes expected revenues. Such a selection rule outperforms selection rules based on response rates or donated amount only. The traditional approach of maximizing response is therefore not the optimal approach to target selection.econometric models;direct marketing;target selection;endogeneity;sample selection

Research proposal: who’s in control? self-directed and self-regulated learning in entrepreneurship training programmes

Several authors in entrepreneurship have called for a multidisciplinary approach in entrepreneurship research (Mishra & Zachary, 2010; Ireland & Webb, 2007). Having a background in educational science and design, I intend to use a multidisciplinary approach, combining insights from the fields of educational science and entrepreneurship. There is more to gain from educational science than Kolb’s experiential learning model. The aim of this research project is to apply a design research approach to develop a set of design principles or methodology for teaching entrepreneurship. The design methodology will be based on the generic model for educational design by Verhagen, Kuiper and Plomp (1999), consisting of an iterative process of analysis (learner, context, needs), design, development, implementation and evaluation (ADDIE) and will be embedded in the design paradigms as articulated by Visscher-Voerman & Gustafsson (2004). The analysis will consist of a combination of a literature study and data collection on adult learning theory, entrepreneurial learning, pedagogy and cognition, the entrepreneurial process and other yet to be defined units of analysis. This analysis will result in a set of design criteria and two possible options to proceed from: (1) a full design to validate all design criteria, (2) the validation of a selection of the design criteria by conducting (quasi) experiments. Both options will include all phases of the design process. The outcome of this research project will be a set of validated design principles/heuristics for teaching entrepreneurship, which will provide guidelines for practitioners in entrepreneurship education. Once validated, these design criteria can also be used to develop an evaluation tool to assess the quality of entrepreneurship education. Apart from being practically relevant, the research will also have theoretical implications. The integration of insights from educational science and entrepreneurship may offer new perspectives and advance existing theories in both fields. The application of a design research approach will also add to the body of knowledge of design research, in both fields

Toward Automatic Interpretation of Narrative Feedback in Competency-Based Portfolios

Self-directed learning is generally considered a key competence in higher education. To enable self-directed learning, assessment practices increasingly embrace assessment for learning rather than the assessment of learning, shifting the focus from grades and scores to provision of rich, narrative, and personalized feedback. Students are expected to collect, interpret, and give meaning to this feedback, in order to self-assess their progress and to formulate new, appropriate learning goals and strategies. However, interpretation of aggregated, longitudinal narrative feedback has been proven to be very challenging, cognitively demanding, and time consuming. In this article, we, therefore, explored the applicability of existing, proven text mining techniques to support feedback interpretation. More specifically, we investigated whether it is possible to automatically generate meaningful information about prevailing topics and the emotional load of feedback provided in medical students' competence-based portfolios (N = 1500), taking into account the competence framework and the students' various performance levels. Our findings indicate that the text-mining techniques topic modeling and sentiment analysis make it feasible to automatically unveil the two principal aspects of narrative feedback, namely the most relevant topics in the feedback and their sentiment. This article, therefore, takes a valuable first step toward the automatic, online support of students, who are tasked with meaningful interpretation of complex narrative data in their portfolio as they develop into self-directed life-long learners

Q fever in the Netherlands:A sero-epidemiological survey among human population groups from 1968 to 1983

A sero-epidemiological survey, using an indirect immunofluorescence test for IgG against Coxiella burnetii (phase II), was carried out in the Netherlands. Serum samples taken in 1968, 1975, 1979 and 1983 were tested. Occupational groups with a supposedly high risk of infection (veterinarians, residents of dairy farms and taxidermists) showed a significantly higher percentage of seropositives than defined controls. The percentage of seropositive amateur wool spinners was significantly higher than that of the controls from the same region. Since 1968 there has been no increase in the percentage of infected persons, indicating that, contrary to earlier assumptions, Q fever has been endemic in The Netherlands for a long time already. The increase in numbers of notified cases of overt Q fever is considered to be the result of the recent introduction of a sensitive indirect immunofluorescence test for IgM antibodies against C. burnetii. Antibody percentages in all age classes between 1 and 64 years were much alike, suggesting that most infections occur in early childhood. This is in accordance with the finding that 35% of our patients are younger than 3 years. The possibility of infection related to childbirth and lactation is discussed.</p

Can healthcare choice be predicted using stated preference data?

Lack of evidence about the external validity of Discrete Choice Experiments (DCEs)-sourced preferences inhibits greater use of DCEs in healthcare decision-making. This study examines the external validity of such preferences, unravels its determinants, and provides evidence of whether healthcare choice is predictable. We focused on influenza vaccination and used a six-step approach: i) literature study, ii) expert interviews, iii) focus groups, iv) survey including a DCE, v) field data, and vi) in-depth interviews with respondents who showed discordance between stated choices and actual healthcare utilization. Respondents without missing values in the survey and the actual healthcare utilization (377/499 = 76%) were included in the analyses. Random-utility-maximization and random-regret-minimization models were used to analyze the DCE data, whereas the in-depth interviews combined five scientific theories to explain discordance.