Robustness to the unavailability of data in block designs

We present general results for finding or boundingt _maxB , the maximum number of arbitrary whole blocks of observations which can be removed from a block design, and still leave all of the elementary treatment contrasts estimable. The block sizes may be larger than the number of treatments. The results are applied to BBDs, reinforced BIBDs and BBDs, BTIBDs, and a series of variance balanced incomplete block designs with two block sizes. Also given for most of these designs, are results fort _max, the maximum number of arbitrary, scattered observations that can become unavailable, and still leave all of the elementary treatment contrasts estimable.The work was undertaken while Dr. Whittinghill was visiting Ohio State University, and supported by a grant from the Natural Sciences Division, Colby College, Waterville, Maine.     

Aggregation effects on price and expenditure elasticities in a quadratic almost ideal demand system

Abstract.  While it is well known that demand elasticities calculated at the macro level will in general differ from those calculated at the micro level because of aggregation effects, there remain the questions of how large the effects are and how they vary with the degree of inequality in the income distribution. We explore these questions with models based on a quadratic version of the Almost Ideal Demand System. We investigate the elasticity differences theoretically and then calibrate the models and generate numerical results, using income data for seven countries with widely different distributions. The aggregation effects are found generally to be rather small, even with highly unequal income distributions.     

Forecasting first births

This study is concerned with one aspect of the family cycle, namely, the transition from young married to young married with small children. The focus is on developing models to forecast entries into this latter stage for the purpose of marketing research. "Using ordinary least squares, forecasting models were estimated for (1) total number of first births, (2) number of white first births, and (3) number of nonwhite first births." Models are estimated for both the United States and California using data from official sources.     

Forecasting and random processes

On the simple model of a (univariate) random process some general problems of “random logic” are discussed. New random approaches to explorative, normative and systematic (normex) forecasting are developed, and some applications are suggested.     

EFFECT OF GROUPING OF DATA ON THE DIVERGENCE BETWEEN LASPEYRES AND PAASCHE FORMS OF QUANTUM INDEXES*

Historical data for the manufacturing industry in the United States and United Kingdom are quoted, showing in most cases divergences between Laspeyres and Paasche forms of the quantum index that are by no means negligible. When the Paasche index for two of the series is recalculated with quantity indicators for industries instead of for products, the divergence is greatly reduced, and when quantity indicators for industry groups are substituted it almost disappears. This raises some questions about the practices of econometricians and statisticians, which are discussed. In a mathematical appendix by E. R. Coleman it is suggested that the grouping effect referred to does not depend on the particular way in which the data are grouped in most quantum indexes.     

A comparison of alternative methods of updating input-output coefficients

In recent years there has been a growing number of input-output models of economies ranging in scale from the rural to the national. While offering invaluable insights into the interaction of sectors within an economy, the input-output model suffers from the fact that its coefficient values are altered over time due particularly to technological change. Two of the prominent techniques designed to update these technical coefficients, the RAS and linear programming methods, are compared herein with regard to changes in U.S. national coefficients between 1963 and 1967. Suggestions for improvements to the latter method are outlined.     

The real action in health care

It's not taking place in the White House or Congress. The show to watch is the boisterous, free-market affair, precipitated by employers fed up with rising medical costs, and carried on by insurers and HMOs scrapping for turf.