Model selection in univariate time series forecasting using discriminant analysis

When a large number of time series are to be forecast on a regular basis, as in large scale inventory management or production control, the appropriate choice of a forecast model is important as it has the potential for large cost savings through improved accuracy. A possible solution to this problem is to select one best forecast model for all the series in the dataset. Alternatively one may develop a rule that will select the best model for each series. Fildes (1989) calls the former an aggregate selection rule and the latter an individual selection rule. In this paper we develop an individual selection rule using discriminant analysis and compare its performance to aggregate selection for the quarterly series of the M-Competition data. A number of forecast accuracy measures are used for the evaluation and confidence intervals for them are constructed using bootstrapping. The results indicate that the individual selection rule based on discriminant scores is more accurate, and sometimes significantly so, than any aggregate selection method.     

Building Better Theory by Bridging the Quantitative–Qualitative Divide*

abstract Qualitative methods for data collection and analysis are not mystical, but they are powerful, particularly when used to build new or refine existing theories. This article provides an introduction to qualitative methods and an overview of tactics for ensuring rigor in qualitative research useful for the novice researcher, as well as more experienced researchers interested in expanding their methodological repertoire or seeking guidance on how to evaluate qualitative research. We focus our discussion on the qualitative analytical technique of grounded theory building, and suggest that organizational research has much to gain by coupling of use of qualitative and quantitative research methods.     

Comparison of test vs. control treatments using distance optimality criterion

We consider the problem of comparison of one test treatment (τ₀) with a set of v control treatments (τ₁, τ₂, …, τ_v) using distance optimality [DS-optimality] criterion introduced by Sinha (1970) in some treatment-connected design settings. It turns out that the nature of DS-optimal designs is quite similar to that for the usual A−, D− and E− optimality criteria. However, the optimality problem is quite complicated in most situations. First we deal with the CRD model and derive DS-optimal allocations for a given set of treatments. The results are almost identical to the A-optimal allocations for such problems. Then we consider a block design set-up and examine the nature of DS-optimal designs. In the process, we introduce the method of weighted coverage probability and maximize the resulting expression to obtain an optimal design. Received: December 1999     

Researching the Drivers of Socially Responsible Purchasing: A Cross-National Study of Supplier Diversity Initiatives

What drives organisations to engage in socially responsible purchasing initiatives? To investigate this important question, this article uses a case-study approach to examine the context within which supplier diversity programmes have emerged in both the U.S. and U.K. The analysis identifies legislative and policy developments, economic imperatives, stakeholder pressures and ethical influences as forces shaping organisational responses. It reveals important contextual differences between U.K. and U.S. experience and offers an empirical and theoretical explanation of corporate behaviour.     

MEASUREMENT OF TECHNICAL EFFICIENCY IN THE NORTH-WEST FRONTIER PROVINCE OF PAKISTAN

The objective of this study is to measure technical efficiency, using a translog frontier production function on cross-sectional data from 397 farms in the North-West Frontier Province of Pakistan in 1988–89. The estimated farm level technical efficiency is found to be dependent upon levels of credit and education, farmers' ages and the extent of land fragmentation. Lack of education, restricted credit and fragmented holdings are found to be causes of inefficiency; hence policies which consolidate holdings, provide credit or educate farmers will tend to improve efficiency in agriculture.     

The distribution of regional earnings in the UK

Utilizing a micro sample of 7317 individuals extracted from the General Household Survey 1973, we show that money earnings and real earnings vary considerably across British regions even when other factors such as education and industry mix are held constant. We also find that real earnings do not follow the pattern of money earnings; if anything, quite the reverse. Whereas monetary rewards are the greatest in the South East of England, real rewards are the greatest in the Midlands and the North East of England. Scottish regions, however, appear to fare the worst in both money and real terms.     

A market segmentation analysis of users of a black-owned neighborhood shopping center

This study examines the characteristics and shopping behavior of urban blacks who patronize a black-owned and managed neighborhood shopping center in a large mid-western city. The shopping center is located in a community that reflects typical inner city characteristics of high unemployment, low income, and classic shortage of necessary retail and commercial facilities. The community promotion analyzed in the study was the shopping center's first formal attempt to promote the mall and provided an opportunity both to measure the traffic and the sales generating impact of the promotion and to learn about the profiles of the center's shoppers. Covered in the study are demographic and socio-economic variables, attitudes toward and perceptions of various characteristics of the mall, and various dimensions of the respondent's retail shopping behavior. Analysis of the characteristics of the shopping center's customers indicates two distinct market segments that live different distances from the mall with sex, income, age, and shopping behavior varying by segment. The hypothesis that the two groups of black shoppers, with different demographic characteristics, will also exhibit different shopping behavior was not rejected, and therefore, the authors could suggest marketing policy and strategy recommendations to management to more effectively reach and satisfy the heavy user of such shopping centers. Alpha Development Corp.     

Experimenting with Supply Chain Learning (SCL): Supplier Diversity and Ethnic Minority Businesses

This paper reports on an innovative UK-based ‘Supply Chain Learning’ (SCL) initiative to encourage the corporate sector to consider supplier diversity in respect of ethnic minority businesses. This follows academic and policy interest in programmes to empower ethnic minority enterprises to achieve breakout to mainstream markets and business growth. The first phase of the initiative, entitled Supplier Development East Midlands (SDEM) is examined. By adopting an inter-organisational action learning approach, some of the key attributes of the programme are delineated, focusing on the recurrent action-reflection cycle taking place in a learning group comprising SDEM, LPOs (Large Purchasing Organisations) and small EMSs (Ethnic Minority Suppliers).