SPC as a tool for creating a successful business measurement framework

Many companies are trying to get to the bottom of what their main objectives are and what their business should be doing. The new Six Sigma approach concentrates on clarifying business strategy and making sure that everything relates to company objectives. It is vital to clarify each part of the business in such a way that everyone can understand the causes of variation that can lead to improvements in processes and performance. This paper describes a situation where the full implementation of SPC methodology has made possible a visual and widely appreciated summary of the performance of one important aspect of the business. The major part of the work was identifying the core objectives and deciding how to encapsulate each of them in one or more suitable measurements. The next step was to review the practicalities of obtaining the measurements and their reliability and representativeness. Finally, the measurements were presented in chart form and the more traditional steps of SPC analysis were commenced. Data from fast changing business environments are prone to many different problems, such as the short previous span of typical data, strange distributions and other uncertainties. Issues surrounding these and the eventual extraction of a meaningful set of information will be discussed in the paper. The measurement framework has proved very useful and, from an initial circulation of a handful of people, it now forms an important part of an information process that provides responsible managers with valuable control information. The measurement framework is kept fresh and vital by constant review and modifications. Improved electronic data collection and dissemination of the report has proved very important.     

The Job Demands-Job Control Model and absence behaviour: results of a 3-year longitudinal study

Empirical results of earlier studies only marginally supported the relevance of Karasek's Job Demands-Job Control Model for absence behaviour. Since longitudinal studies with respect to these relations were largely lacking, a four-wave panel study was carried out using data from 1755 male employees of a technical maintenance firm in the public sector. Job demands, job control, physical working conditions, and the employee's age, education, and health were measured in one year and absenteeism in the same year and in the next 3 years. Data were analysed with linear regression and Poisson regression techniques. The Poisson regression technique was superior to the linear regression technique in explaining absence. Age, health and prior absence were the best predictors of later absence behaviour. With respect to the Job Demands-Job Control Model, the main findings of the study were (1) that job control was significantly associated with a low number of simultaneous and later absence days, and (2) that, contrary to expectations, job demands were also related to a low number of simultaneous and later absence days. These results hold when age, health, education, prior absence, and working conditions are controlled for. Job control and job demands did not predict later absence frequency. In the discussion it is suggested that a high level of job demands may not only be harmful for the well-being of employees but also work as 'a pressure to attend'.     

A general method of constructing E(s2)-optimal supersaturated designs

There has been much recent interest in supersaturated designs and their application in factor screening experiments. Supersaturated designs have mainly been constructed by using the E ( s ²)-optimality criterion originally proposed by Booth and Cox in 1962. However, until now E ( s ²)-optimal designs have only been established with certainty for n experimental runs when the number of factors m is a multiple of n-1 , and in adjacent cases where m = q ( n -1) + r (| r | 2, q an integer). A method of constructing E ( s ²)-optimal designs is presented which allows a reasonably complete solution to be found for various numbers of runs n including n ,=8 12, 16, 20, 24, 32, 40, 48, 64.     

Outcomes of permanent family placement for children of minority ethnic origin

The paper explores the outcomes of permanent family placement for children of minority ethnic origin, using a sample of 254 placements drawn, in the main, from a cohort of 1165 British children placed between 1980 and 1985. Statistical techniques are used to explore the relationship between 'success' (defined, for the purposes of this paper, as the placement not known to have broken down) and a range of variables, including the characteristics of the child, the birth parents and the adoptive parents, and the type of placement. In most respects, the findings are consistent with those of similar studies. Age at placement is found to have an important effect, with success least likely for children placed in the middle age range. Lack of problem behaviours in the children at the time of placement is also found to be associated with success. Variables which are found to have no effect on the probability of success include ethnic origin of the child, whether it is an adoptive or permanent foster placement, and whether contact with birth parents continued after placement. There was an interesting gender effect in that boys did better in 'transracial' than in 'matched' placements, but the opposite was the case for girls.     

Coaching von Managern in Ostdeutschland

Coaching managers in East Germany The author discusses problems of the transformation process in East Germany. The main thesis: The patterns of behaviour established in the former DDR are still effective. This is demonstrated by the situation of managers and the company’s internal milieus. In order to support managers active in East Germany it is important, to know the patterns practised in the DDR and to transform them into those, which are compatible with the free enterprise economy. To increase the motivation, managers should be encouraged to refer to the former experiences of community and to meet in this way the specific needs of the employees.     

Rank tests in the two-sample scale problem with unequal and unknown locations

The two-sample scale problem is studied in the case of unequal and unknown location parameters. The method proposed is based on the idea of Moses (1963) and it is distribution-free. The two samples are separated into random subgroups of the same sizek. It is proposed to choosek=4 and to apply the Wilconxon test or the Savage test to the ranges or sample variances of the subgroups. The asymptotic power functions of the tests are compared. For small and moderate sample sizes simulations are carried out. Relations to some other procedures, especially to the method of Compagnone and Denker (1996) are briefly discussed.     

Faktoren der Veränderung des Selbst bei computervermittelter Kommunikation

Computer-mediated communication (CMC) influences the users’ self. Different expectations are currently made towards how the self may arise in an ‘a-social’ setting during the use of modern “Information” and communication technologies. Some of these discourses even observe a new potential for self-constructions. The conceptual frame of the paper is delivered by the combination of different social scientific approaches coming from Social Psychology, Sociology and Communications Studies. Based upon a series of experiments the paper investigates how the social self develops in CMC. Overall the self is moderated by the characteristics of the channel, by psycho-social and finally by socialisation variables. The influence of the channel is marked by immediate effects of certain cues. The psycho-social variable is the individual versus joint usage of CMC. The sociological dimension is the familiarity with CMC. Finally a model is discussed that introduces the prototypical character of CMC for the development of the self in further forms of mediated interpersonal communication.     

The quincunx: history and mathematics

Received: December 30, 1999; revised version: July 19, 2000     

Adaptive weights smoothing with applications to image restoration

We propose a new method of nonparametric estimation which is based on locally constant smoothing with an adaptive choice of weights for every pair of data points. Some theoretical properties of the procedure are investigated. Then we demonstrate the performance of the method on some simulated univariate and bivariate examples and compare it with other nonparametric methods. Finally we discuss applications of this procedure to magnetic resonance and satellite imaging.