Experience with using the Box-Cox transformation when forecasting economic time series

Experience using twenty-one actual economic series suggests that using the Box-Cox transform does not consistently produce superior forecasts. The procedure used was to consider transformations $\text{x}{}^{\mathrm{(\lambda )}}\text{=}\text{(x}{}^{\mathrm{\lambda }}\text{?1)}\text{λ}$, where λ is chosen by maximum likelihood, a linear ARIMA model fitted to x^(λ) and forecasts produced, and finally forecasts constructed for the original series. A main problem found was that no value of λ appeared to produce normally distributed data and so the maximum likelihood procedure was inappropriate.     

Model Uncertainty, Limited Market Participation, and Asset Prices

We demonstrate that limited participation can arise endogenouslyin the presence of model uncertainty and heterogeneous uncertainty-averseinvestors. When uncertainty dispersion among investors is small,full participation prevails in equilibrium. Equity premium isrelated to the average uncertainty among investors and a conglomeratetrades at a price equal to the sum of its single-segment components.When uncertainty dispersion is large, investors with high uncertaintychoose not to participate in the stock market, resulting inlimited market participation. When limited participation occurs,participation rate and equity premium can decrease in uncertaintydispersion and a conglomerate trades at a discount.     

Computer conferencing: The exchange of experience

This article considers computer conferencing within a larger framework, showing its relationship with other forms of electronic information exchange. The author, recognizing the lack of empirical data available, describes the experience of operational trials of small research communities begun in 1977. The trials allow an assessment of information exchange and promote the existence of a population of experienced users.     

Editorial comment : Our clientele

The problem considered is that of aiding large, technically unsophisticated groups to make quantitative policy decisions in real time in one sitting. Utility theory approaches, as well as Delphi and cross-impact matrices are discussed. The application of computer technology to such decision making situations is considered and the results of implementing such technology with several groups is discussed.     

The use of structural modeling for technology assessment

Structural modeling (SM) techniques are a set of geometric, semi-quantitative tools that can assist in organizing a technology assessment (TA), developing a rough overview of it, and analyzing various component problems. In this project about 100 SM techniques were identified and seven were tested in detail: ISM, ELECTRE, SPIN, KSIM, QSIM, IMPACT, and XIMP. Guidelines were developed to help the assessor in the choice and proper use of such tools.