A new product growth model with a dynamic market potential

Traditional new product diffusion models have assumed a constant market potential over the planning horizon for forecasting product adoptions. This assumption is conceptually unsound and is likely to yield either theoretically unacceptable parameter estimates of the model or poor demand forecasts. This paper presents a dynamic growth model which relaxes this assumption. Model illustrations, limitations and further extensions are included.     

Effects of positive attitude on earnings: Evidence from the US longitudinal data

To examine whether or not the worker's attitude to life affects his/her earnings, this study estimates wage equations with positive attitude as an explanatory variable under different econometric specifications. The results obtained from both cross-sectional and panel data confirm that positive and optimistic attitude to life influence the worker's wages positively, and that the magnitude of this effect is comparable to or even higher than the individual effects of the standard human capital variables on earnings. The study further demonstrates that in addition to its direct effects, positive attitude also affects earnings indirectly through its effects on schooling.     

Estimating the demand for risky assets via the indirect expected utility function

This article obtains demand functions for risky assets without making a priori assumptions about the form of the utility function. In a simple portfolio model, the envelope theorem is applied to the indirect expected utility function to derive estimating equations. Tests for the existence of constant absolute or constant relative risk aversion are also developed. Empirical estimation of the demand for financial assets held by U.S. households for the period 1946–1985 indicates that aggregate household behavior is consistent with the existence of constant relative risk aversion, with the coefficient of risk aversion having a value of approximately 1.3.The authors gratefully acknowledge helpful comments from the editor and an anonymous referee.     

Pregnancy outcome and the time required for next conception

Abstract Variations in the time required for next conception by outcome ofthe preceding pregnancy, and the age of woman, are studied for Taiwanese women. Pregnancy interval, defined as the period between the end of one pregnancy and the beginning of the next, is taken as a measure of the time required for the next conception. The averages and variances of pregnancy intervals are estimated from reports of pregnancies occurring in a probability sample of 2,443 married women, aged 20-39, living in Taichung (Taiwan) in 1962. The effects of 'truncation bias' and 'memory bias' on the two moments of pregnancy intervals are estimated indirectly by cross-classifying women according to their ages at interview and their ages at the beginning (or end) of each pregnancy interval. The moments of post-partum amenorrhoea are, then, estimated indirectly from the moments of pregnancy intervals. The effects of truncation bias and memory bias are compensatory in this sample. In the absence of contraception, women, on an average, took longer to conceive following a live birth than following a foetal death. The time taken for next conception increases as women become older irrespective of the outcome of the preceding pregnancy.     

Morbidity and multi-morbidity in Australia: Evidence from the national health surveys

This paper examines the prevalence of reported morbidity in Australia during the two time periods 1977–78 and 1989–90. It utilizes data from the National Health Surveys conducted by the Australian Bureau of Statistics in the respective years. Prevalence of reported multi-morbidity is also examined for persons who reported one or more of ten specific long-term conditions in the 1989–90 survey. The study found that the prevalence of morbidity increased in Australia between the survey years, which occurred, as in some other low-mortality countries, along with mortality reduction over this period. Females reported higher morbidity than males but the sex differential narrowed over time. The Aboriginal population had lower morbidity than the total population of Australia but the difference was not statistically significant. For some specific conditions, prevalence of morbidity was higher for the Aboriginal population. Capital city dwellers in the states had higher prevalence of morbidity than non-capital city dwellers. The Australian Capital Territory had the highest and the Northern Territory the lowest prevalence of morbidity among all states and territories of Australia.     

On Gini's diversity measure

The purpose of this paper is to investigate the optimal properties of Gini's diversity measure. It is shown that as number of species increase , Gini's diversity approaches asymptotically to unity.     

The propagation of lean thinking in SMEs

Abstract

Small and Medium-sized Enterprises (SMEs) play a pivotal role in economic growth, industrial output, and employment creation. However, SMEs are often ignored by researchers as far as the adoption of lean is concerned in comparison to Large Enterprises (LEs). Therefore, the literature regarding lean implementation in SMEs is not conspicuous, and many SMEs have only a limited understanding and awareness of lean. This paper offers a comprehensive literature review with a focus on the implementation of lean in SMEs and explores the applicability of lean thinking in such environments. An attempt is made to provide an analysis of lean practices that have been applied in SMEs and critical success factors for lean transformation in SMEs. It also contributes to the field of lean implementation research by proposing a framework for lean in SMEs and identifies the scope of future research.     

Relative efficiency of a parameter for a M/G/1 queueing system based on reduced and full likelihood functions

The present paper derives the relative efficiency of a parameter for the M/G/1 queueing system based on reduced and full likelihood functions. Monte Carlo simulations were carried out to study the finite sample properties for estimating the parameters of a M/G/1 queueing system. The simulation runs were conducted using various traftic intensities with increaseing sample sizes. The simulation results indicate that the loss in efficiency is quite small due to the use of a reduced likelihood function approach for estimating the parameter instead of the full likelihood, even for a moderate sample size of 50