A new approach to modelling sigmoidal curves

Growth and diffusion phenomena have become of great interest to investigators in many disciplines, such as Biology, Demography, Economy, Agriculture, etc. These processes are generally analyzed by means of growth curves. As, in nature, it is not possible for any variable to continue growing indefinitely, we can consider any growth process to have an upper limit or saturation level. Thus, should a model represent a growth phenomenon, it will be described by a sigmoidal or S-shaped curve. There are a wide variety of growth models in general and specific literature. Of these, the logistic model is without doubt one of the most studied in practice, as well as some modifications of it, including recent investigations directed to the decomposition of a growth curve into various logistic components [Technol. Forecast. Soc. Change 47 (1994) 89; Technol. Forecast. Soc. Change 61 (1999) 247.]. In all the cases above, the adopted approach includes fitting the trend curve to the data by means of a well-known estimation procedure, such as least squares. We suggest a somewhat different approach, which consists of expressing the model through its differential equation and searching for a functional specification for the variable representing growth rate. Two series have been chosen from the recent literature in order to illustrate the methodology presented.     

Do values or goals better explain intent? A cross-national comparison

Among six major lines of inquiry on motivations, two theories are especially pertinent to consumer behavior studies: values and goals. Several studies show that consumer behavior can be predicted on the basis of values or goals; this study examines which are the stronger predictors by presenting a cross-cultural comparison of the values and goals that may influence the behavioral intentions of U.S., Chinese, and French students to study abroad. As a service, study abroad has financial implications, represents a choice, and competes with other educational products. Therefore, goals appear to explain behavioral intentions better than do values, except among U.S. students. The goals and values associated with behavioral intentions differ across cultures and have different perceived dimensions, such that items cluster on those dimensions with specific meanings, depending on the culture. The different influences of values and goals on behavioral intentions may help marketing managers design more efficient marketing strategies in international markets. This paper thus contributes to the marketing literature by suggesting that national cultures moderate the effect of values and goals on consumer intentions.     

Introducing the impact of technology: a ‘neo-contingency’ HRM Anglo-French comparison

The paper analyses the impact of technological and national-culture factors on certain HRM policies and practices in Britain and France. This perspective supports the neo-contingency approach, which does not claim primacy for either the technological or the national-cultural factors shaping HRM policies and practices. HR managers in each country in high-, mid- and low-tech firms were surveyed. The relevance in the diffusion of certain patterns of HRM policies and practices advocates that employees working in intensive technology firms need a creative and adaptive HR management approach. The differences found in the application of the HRM practices studied between the two countries are illustrated through the educational system, which is different in France and Britain.     

Familiarity and competence diversity in new product development teams: Effects on new product performance

When developing new products, most firms use cross-functional teams, but research on the effect of functional diversity on new product performance returns heterogeneous results. We propose a measure of competence diversity that is more comprehensive than the common functional diversity proxy. Empirical findings, based on a survey of 142 product and sales managers, support the improved predictive validity of our scale. We further observe a mediating effect of the instrumental use of information in the competence diversity–new product performance relationship. Finally, we discuss the moderating effect of familiarity among team members on the relationship between competence diversity and the instrumental use of information. All authors contributed equally to this article and are listed in random order.     

Internet adoption in France

The diffusion of innovation models developed in marketing are applied to the adoption of the Internet in France. The most classic of the models, the Bass model, is adjusted to the estimations of Médiamétrie. The non-uniform influence model has been utilised to introduce the network externalities of an increasing influence of previous adopters on the adoption process. Some predictions of the penetration of the Internet in France are proposed.