An important application of multiple regression is predictor selection. When there are no missing values in the data, information criteria can be used to select predictors. For example, one could apply the small‐sample‐size corrected version of the Akaike information criterion (AIC), the (AICC). In this article, we discuss how information criteria should be calculated when the dependent variable and/or the predictors contain missing values. Therewith, we extensively discuss and evaluate three models that can be employed to deal with the missing data, that is, to predict the missing values. The most complex model, that is, the model with all available predictors, outperforms the other models. These results also apply to more general hypotheses than predictor selection and also to structural equation modeling (SEM) models. 相似文献
Changes in the nature of science as a social practice were fundamentally organic and endogenous in nature prior to the 1970s. Since then changes in UK public science has been policy-led and the imperatives exogenous. This shift was the result of attempts to achieve strategic managed change in the sector using new public management (NPM) techniques. This paper explores the discourses that promoted the change effort and the NPM techniques and processes deployed to this end. It seeks to identify the aims and objectives of the intended strategic change and evaluates the extent to which they have been achieved. Our conclusion is that rather than a planned, strategic change process directed at improved economy, efficiency and effectiveness, what occurred was a poorly processed ideologically driven attempt to achieve political aims. 相似文献
Risk management has a central role in corporate America. Insurance companies frequently manage risk by purchasing reinsurance because it reduces the downside risk (i.e., bankruptcy risk) of an insurer. Because reinsurance is costly, Mayers and Smith (1990, Journal of Business , 63: 19-40) argue that reinsurance purchases should be negatively associated with the diversification of the owners' portfolios. Further, institutional owners play a significant role in equity markets yet we know little about their effect on firm behavior. The purpose of this study is to examine empirically the influence of institutional ownership on reinsurance for a sample of widely held property-liability insurers. We hypothesize that insurers with higher levels of institutional ownership purchase less reinsurance. Using a sample of 45 publicly traded property-liability insurers from 1995 to 1997, we demonstrate that the utilization of reinsurance decreases as the level of institutional ownership increases. This suggests that the diversification of the owners' portfolios is a determinant of the insurers' reinsurance decisions. 相似文献
Measuring the costs of children is of immense practical importance in a range of economic and social policy areas. In this paper, we introduce a new econometric procedure that improves on existing methods for obtaining estimates of such costs from a demand system. We develop, using an extended linear expenditure system, an iterative maximum likelihood estimator that overcomes possible estimation problems that arise from the 2-step estimation procedures employed by earlier authors. We also allow for a more general assumption about the equation “errors”, that of non-zero correlation between the errors for different commodities in the same household. Another important contribution is the development of an estimation procedure for sets of seemingly unrelated regressions where the different sets of equations are linked by some common parameters. The proposed procedure is applied to the 1988–89 and 1993–94 Australian Household Expenditure Surveys and results obtained update estimates of both the commodity-specific and general scales previously obtained for Australia.
Research shows that some narratives and symbolic actions produced by entrepreneurial firms can help to reduce audience uncertainty about their quality and differentiate them from rivals. But can communications via online social media channels – which we characterize as “communicative streams” – be used to reduce uncertainty and enhance differentiation? This seems debatable, given that such streams comprise multiple, brief messages (a) that encode signals lacking narrative cohesion; (b) are only fleetingly accessible; and (c) are minimally customized. We address this puzzle using qualitative methods to compare the communications enacted by eight firms that are using Twitter in order to pursue growth. Our theoretical contribution rests in positing links between specific types of communicative streams and audience responses that reflect reduced uncertainty or enhanced differentiation. Our analysis suggests that firms enacting a “Multi-dimensional” communicative stream (which entails a high volume of posts, a high proportion of which signal quality, relational orientation, distinctiveness, and positive affect) are most likely to elicit audience affirmation of firms' quality and/or distinctiveness. Implications for theory, research methods and practice are discussed. 相似文献
This paper inductively develops an extension to brand positioning theory to understand how individuals seeking work in established organizational fields can effectively position themselves. It does so by analyzing qualitative data on the practices of people in one job category (fashion models) in an established organizational field (fashion), examining them through the lens of concepts adapted from work by Pierre Bourdieu. Four brand positioning practices are identified as relevant for models vying for work in the fashion field: crafting a portfolio, cultivating and demonstrating upward affiliations, complying with occupation-specific behavioral expectations, and conveying field-conforming tastes. Drawing on Bourdieu, we argue more generally that person brand positioning within established organizational fields happens through processes that help to portray a person as having field-specific social and cultural capital that allows them to “stand out,” while acquiring the habitus that allows them to comply with field- and occupation-specific expectations in order to “fit in.” Standing out and fitting in have parallels with—but are not identical to—the processes of establishing and reinforcing points of differentiation and points of parity for product brands. Our study implies that scholars interested in person branding should further develop theories that illuminate variations in brand positioning practices between products and persons. It also suggests that people building person brands should be sensitized to the valued forms of capital and normative expectations in their field that enable them to stand out while fitting in. 相似文献