Accounting for time-dependent treatment use when developing a prognostic model from observational data: A review of methods

Failure to account for time-dependent treatment use when developing a prognostic model can result in biased future predictions. We reviewed currently available methods to account for treatment use when developing a prognostic model. First, we defined the estimands targeted by each method and examined their mechanisms of action with directed acyclic graphs (DAGs). Next, methods were implemented in data from 1,906 patients; 325 received selective β-blockers (SBBs) during follow-up. We demonstrated seven Cox regression modeling strategies: (a) ignoring SBB treatment; (b) excluding SBB users or (c) censoring them when treated; (d) inverse probability of treatment weighting after censoring (IPCW), including SBB treatment as (e) a binary or (f) a time-dependent covariate; and (g) marginal structural modeling (MSM). Using DAGs, we demonstrated IPCW and MSM have the best properties and target a similar estimand. In the case study, compared to (a), approaches (b) and (e) provided predictions that were 1% and 2% higher on average. Performance (c-statistic, Brier score, calibration slope) varied minimally between approaches. Our review of methods confirmed that ignoring treatment is theoretically inferior, but differences between the prediction models obtained using different methods can be modest in practice. Future simulation studies and applications are needed to assess the value of applying IPCW or MSM to adjust for treatments in different treatment and disease settings.     

360 degree feedback: how many raters are needed for reliable ratings on the capacity to develop competences,with personal qualities as developmental goals?

360 degree feedback is a widely used technique in the area of strategic human resource management (SHRM) and strategic human resource development (SHRD). The reliability of 360 degree feedback on the capacity to develop personal qualities has been investigated. This study shows to what extent the number of raters is related to an increasing reliability and an enhancement of correlation between supervisor and peer ratings. Ten raters are needed to reach a satisfying reliability level of 0.7 for the rating of the capacity to develop personal qualities, while six raters are needed for a reliability level of 0.7 with regard to the rating of motivation to develop these qualities. The use of two or three peer raters, as is common in the daily HRM/HRD practice, results in low reliability levels and in low agreement between supervisor and peer ratings. These results imply that 360 degree feedback is more useful in a personal growth system than in an administrative system, where the outcomes of the feedback are considered to be objective representations of work behaviour. Further implications for the SHRM/SHRD practice, especially concerning the development of competences, with personal qualities as developmental goals, are discussed.     

Normative expectations in systems innovation

This paper is concerned with the way technological expectations are generated, articulated and deployed in processes of large-scale socio-technical change. We argue that expectations are intrinsic to all social action, so that visions of the future are both ubiquitous and context-specific. Agents will act in relation to private visions of the future that are complexly related to shared or collective visions. Characteristic features and forms of visions as they relate to socio-technical regimes are identified, and the specific roles visions play in the context of actor networks engaged in processes of systems innovation are discussed. Visions are seen as 'bids' that are deployed by actors in processes of coalition-formation and coordination. Examples from a range of visions of more sustainable systems are used to illustrate the main arguments. The paper ends by discussing the normative features of socio-technical expectations.     

Sustainable hospitality: a meaningful notion?

This paper explores the concept of sustainable hospitality. The relevance and status of this area of enquiry are assessed by discussing the current status of the concepts involved. These discussions are then linked to progress made in sustainable hospitality both in research and practical applications in the hospitality industry. At least six principal schools of thought within hospitality are noted: hospitality science, hospitality management, hospitality studies, the “three domain school”, the systems thinking school and the pragmatic tradition. This complexity and lack of clear definition are problems. The differences between sustainability and sustainable development, and between weak and strong sustainability add further complexities. This paper shows that progress in both sustainable hospitality and tourism has been limited by these problems. A series of technical, ethical and commercial problems are discussed. However, while sustainable hospitality as a research area is still in its infancy, it is concluded that it is very relevant within the wider context of sustainable tourism research, based on its impact and its specific position within the social–ecological–economic systems under investigation. Key areas of future work are suggested, notably to better understand the impacts of hospitality on the triple bottom line, and to explore systems approaches towards implementation.     

Social class, social mobility and mortality in the Netherlands, 1850–2004

This study uses data from a random sample of births in the Netherlands during the period 1850–1922 to examine the relationships between social class, social mobility and mortality at middle and old age. Population registers and personal cards covering the period from 1850 to 2004 for all Dutch provinces were used to reconstruct individual life histories of 14,900 births. For men we did not find an effect of the social class of origin (using two different SES-classifications) on mortality in age group 18 to 35. We also did not observe an effect of own social class on mortality after age 35. For women effects of social class of origin and social class of husband were generally absent as well. Our conclusion is that the standard ideas about the negative effects of processes of industrialization and urbanization on the duration of life do not seem to apply to the Netherlands. Where one lived mattered more for survival than the social class one belonged to.     

Sealed-bid auction of Netherlands mussels: Statistical analysis

This article presents an econometric analysis of the many data on the sealed-bid auction that sells mussels in Yerseke town, the Netherlands. The goals of this analysis are obtaining insight into the important factors that determine the price of these mussels, and quantifying the performance of an individual purchase manager. Besides a case-study, the article is a general study on the role of auctions in supply chains and on hedonic price factors.     

Offshoring strategy: Motives,functions, locations,and governance modes of small,medium-sized and large firms

How does firm size impact on a firm's offshoring strategy? Are the underlying motives for offshoring, the particular functions considered, the locations to relocate, and the particular governance mode different for small, medium-sized and large firms? In this paper, cost, resource and entrepreneurial drivers are investigated for their relationship with firm size. Moreover, we hypothesize on the relationship between function, location and governance mode choices of offshoring and firm size. Using multi-country data of the Offshoring Research Network (ORN), we present empirical evidence on the three offshoring driver categories and function, location and governance mode choices of small, medium-sized and large firms. The results show offshoring might be used as cost, resource or entrepreneurial strategy. Cost drivers are most important for large and small firms, whereas resource drivers are especially important for medium-sized and large firms. Entrepreneurial drivers are most important for medium-sized firms, just like these firms have a relatively stronger preference for nearshoring. Small firms mostly offshore competence exploring activities, whereas large firms relocate competence exploiting activities.     

Structural differentiation and corporate venturing: The moderating role of formal and informal integration mechanisms

Research has suggested that corporate venturing is crucial to strategic renewal and firm performance, yet scholars still debate the appropriate organizational configurations to facilitate the creation of new businesses in existing organizations. Our study investigates the effectiveness of combining structural differentiation with formal and informal organizational as well as top management team integration mechanisms in establishing an appropriate context for venturing activities. Our findings suggest that structural differentiation has a positive effect on corporate venturing. In addition, our study indicates that a shared vision has a positive effect on venturing in a structurally differentiated context. Socially integrated senior teams and cross-functional interfaces, however, are ineffective integration mechanisms for establishing linkages across differentiated units and for successfully pursuing corporate venturing.     

Decomposing sales elasticities on segmented markets

In this study we consider an extension of the well-known model developed by Lambin, Naert and Bultez (henceforth, the LNB-model). The LNB-model can be used to assess the effects of competitive actions and reactions. The extension of the LNB-model considered in this study accounts for differences between the reactions of competitors operating on different segments. The model is tested empirically using data on the market of a frequently purchased non-durable consumer good. Three different segments are considered on this market. The outcome of the extended model is compared with the results of the LNB-model.