The promises of practice

Practice has become a topic of increasing empirical and conceptual concern within sociology and neighbouring fields. ‘Practice’ can refer to a location or it can refer to action. It is possible to be ‘in practice’, to ‘have a practice’ or to be ‘constituted by practice’. Practice can be a cause, an effect or an explanation. Within science and technology studies (STS), the practice orientation is simultaneously analytical – in the form of various practice theories – and empirical, in that research objects are often defined as ‘practices’. Focusing on a range of examples, especially ethnomethodological, this paper examines some implications and problems that follow when practice slides unnoticed between empirical and conceptual registers. Arguing that a reconsideration of practice thinking is important in order to retain its vigour, we outline a view of practice as a ‘factish’, at once conceptual and empirical, which facilitates analyses of practical ontologies and their transformations. This informs a final discussion of the politics and promises of practice.     

Sensitivity analysis of longitudinal data with intermittent missing values

Several models for longitudinal data with nonrandom missingness are available. The selection model of Diggle and Kenward is one of these models. It has been mentioned by many authors that this model depends on untested modelling assumptions, such as the response distribution, from the observed data. So, a sensitivity analysis of the study’s conclusions for such assumptions is needed. The stochastic EM algorithm is proposed and developed to handle continuous longitudinal data with nonrandom intermittent missing values when the responses have non-normal distribution. This is a step in investigating the sensitivity of the parameter estimates to the change of the response distribution. The proposed technique is applied to real data from the International Breast Cancer Study Group.     

THE OPTIMAL TAXATION OF ASSET INCOME WHEN GOVERNMENT CONSUMPTION IS ENDOGENOUS: THEORY,ESTIMATION AND WELFARE

This paper derives the Ramsey optimal fiscal policy for taxing asset income in a model where government expenditure is a function of net output or the inputs that produce it. Extending work by Kenneth L. Judd, I demonstrate that the canonical result that the optimal tax on capital income is zero in the medium to long term is a special case of a more general model. Employing a vector error correction model to estimate the relationship between government consumption and net output or the factor inputs that generate it for the United States between 1948Q1 and 2015Q4, I demonstrate that this special case is empirically implausible, and show how a cointegrating vector can be used to determine the optimal tax schedule. I simulate a version of the model using the empirical estimates to measure the welfare implications of changing the tax rate on asset income, and contrast these results with those generated in a version of the model where government consumption is purely exogenous. The shifting pattern of welfare measurements confirms the theoretical results. I calculate that the prevailing effective tax rate on net asset income in the United States between 1970 and 2014 averaged 0.449. Hence abolishing the tax completely does generate welfare improvements, though only by the equivalent of between 1.103% and 1.616% permanent increase in consumption—well under half the implied welfare benefit when the endogeneity of the government consumption is ignored. The maximum welfare improvement from shifting part of the burden of tax from capital to labor is the equivalent of a permanent increase in consumption of between only 1.491% and 1.858%, and is attained when the tax rate on asset income is lowered to between 0.148 and 0.186. Allowing the tax rate to vary over time raises the maximum welfare benefit to 1.865%. All the results are very robust to a wide range of elasticities of labor supply. (JEL E62, H21, H50)     

Mapping the organization a methodological approach to organizational change initiation

facturers have realized that in order to survive in this market a new way of doing business is required. Initiating and planning changes is the focus of this paper, which describes a new methodology developed with the Israeli Military Industries. The methodology is designed to promote and initiate change in operations by defining a well-structured approach to Abstract. The defence industry is facing a shrinking market and tough competition. Most defence contractors and manu     

A Note on the Relationship Among Capacity,Pricing, and Inventory in a Make‐to‐Stock System

We address the simultaneous determination of pricing, production, and capacity investment decisions by a monopolistic firm in a multi‐period setting under demand uncertainty. We analyze the optimal decision with particular emphasis on the relationship between price and capacity. We consider models that allow for either bi‐directional price changes or models with markdowns only, and in the latter case we prove that capacity and price are strategic substitutes.     

Efficient Nonparametric Estimation from Kin–Cohort Data

In a Kin–Cohort design, genotype data are first obtained from a sample composed mostly of individuals who have experienced onset of a disease. Disease history data are then obtained from their relatives. The design is useful when examining the conditional distribution, given genotype, of phenotypes such as disease severity scores when some genotypes are rare. Here, the problem of combining the genotype data in the probands with the phenotype information in their relatives is considered. A class of unbiased estimators is described, the optimal member which reaches the semiparametric efficiency bound is identified, and results from simulation experiments are discussed.     

Collective Decision-Making: the Analytic Hierarchy Process

Analytic Hierarchy Process (AHP) is a method to improve decision making whose application here is to complex environments. “A.H.P.” involves structuring a decision into a hierarchy, determining relative priorities for the elements in the hierarchy, and combining the numbers into overall weights estimating each decision outcome. The need for decision aids such as AHP, is supported by the literature, which suggests that even experts can contend with only limited amounts of information and tend to arrive at decisions in a simple fashion. AHP allows for using more information to make decisions in more complex ways. This leads to more coherent decisions. In the case presented AHP helped a committee make resource allocation decisions in an urban renewal project in Israel. The example highlights the usefulness of AHP in group settings. Areas of disagreement were easily identified and discussed. This diffused much of the tension typical of these proceedings.