To date, the phenomenon of entrepreneurship has lacked a conceptual framework. In this note we draw upon previous research conducted in the different social science disciplines and applied fields of business to create a conceptual framework for the field. With this framework we explain a set of empirical phenomena and predict a set of outcomes not explained or predicted by conceptual frameworks already in existence in other fields.

The Promise of Entrepreneurship as a Field of Research

计量经济分析 = Econometric analysis

This survey reviews the growing use of patent data in economic analysis. After describing some of the main characteristics of patents and patent data, it focuses on the use of patents as an indicator of technological change. Cross-sectional and time-series studies of the relationship of patents to R&D expenditures are reviewed, as well as scattered estimates of the distribution of patent values and the value of patent rights, the latter being based on recent analyses of European patent renewal data. Time-series trends of patents granted in the U.S. are examined and their decline in the 1970s is found to be an artifact of the budget stringencies at the Patent Office. The longer run downward trend in patents per R&D dollar is interpreted not as an indication of diminishing returns but rather as a reflection of the changing meaning of such data over time. The conclusion is reached that, in spite of many difficulties and reservations, patent data remain a unique resource for the study of technical change.

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Patent Statistics as Economic Indicators: A Survey

To assess the effects of a firm's network of relations on innovation, this paper elaborates a theoretical framework that relates three aspects of a firm's ego network—direct ties, indirect ties, an...

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Collaboration Networks, Structural Holes, and Innovation: A Longitudinal Study:

Offering a unifying theoretical perspective not readily available in any other text, this innovative guide to econometrics uses simple geometrical arguments to develop students' intuitive understanding of basic and advanced topics, emphasizing throughout the practical applications of modern theory and nonlinear techniques of estimation. One theme of the text is the use of artificial regressions for estimation, reference, and specification testing of nonlinear models, including diagnostic tests for parameter constancy, serial correlation, heteroscedasticity, and other types of mis-specification. Explaining how estimates can be obtained and tests can be carried out, the authors go beyond a mere algebraic description to one that can be easily translated into the commands of a standard econometric software package. Covering an unprecedented range of problems with a consistent emphasis on those that arise in applied work, this accessible and coherent guide to the most vital topics in econometrics today is indispensable for advanced students of econometrics and students of statistics interested in regression and related topics. It will also suit practising econometricians who want to update their skills. Flexibly designed to accommodate a variety of course levels, it offers both complete coverage of the basic material and separate chapters on areas of specialized interest.

Estimation and Inference in Econometrics

Utilizing a unique data set, Zoltan Acs and David Audretsch provide a rich empirical analysis of the increased importance of small firms in generating technological innovations and their growing contribution to the U.S. economy. They identify the contributions made by both small and large firms to the innovative process and the manner in which market structure, and the firm-size distribution in particular, responds to technological change. The authors' analysis relies on traditional theories of industrial organization and tests existing hypotheses, many of them previously untested due to data constraints.Innovation and Small Firms brings together two large data bases recently released by the U. S. Small Business Administration - one directly measuring innovative activity for large and small firms, the other providing a detailed census of economic activity for all manufacturing firms and plants across a broad spectrum of industries.Acs and Audretsch describe and evaluate the data bases in the context of the literature on innovation, market structure, and firm size. They present their findings on the presence of small firms, small-firm entry in manufacturing, small-firm growth and flexible technology, and mobility and firm size. They compare static and dynamic measures of small-firm viability and address the relationships between R&D, innovation, and productivity, and analyze the interaction between technological regimes and the role of government in innovation.Zoltan Acs is an Associate Professor of Economics at the Merrick School of Business, the University of Baltimore. David Audretsch is a Research Fellow at the Wissenschaftszentrum Berlin fur Sozialforschung in West Berlin.

Innovation and Small Firms

Probes the impact that various industry characteristics have on the innovative output of firms. Data used for this analysis were gathered by the U.S. Small Business Administration (SBA) through examination of over 100 technology, engineering, and trade journals. The SBA data on new products, processes and services introduced to the market in 1982 was broken down by firm size, industry, and significance. Innovation activity is measured by the number of innovations in each four-digit SIC industry. Prior studies have utilized such data as patents and stock market value for large firms; through this more direct measure of innovation activity, several key findings are made. In an industry composed primarily of large firms, the level of innovation will be higher, though that activity will occur mostly in the smaller firms of that industry -- i.e., innovation appears to be an important competitive strategy for small firms in that environment. Results indicate that lower levels of concentration are associated with increased innovation activity. Further, as industry R&D increases, the number of innovations increases, but this increase is at a decreasing rate. Unionization is found to be negatively related to innovation activity. Although the results do not shed much light on the exact relationship between R&D, appropriability, and innovation activity, they do show support for the proposition that differences in economic and technological environments lead to differences in the innovation activity of large and small firms. (SRD)

Innovation in Large and Small Firms: An Empirical Analysis

Local Geographic Spillovers between University Research and High Technology Innovations

Patents and innovation counts as measures of regional production of new knowledge

The authors present a model suggesting that innovative output is influenced by RD and (2) these d eterminants have disparate effects on large and small firms. Copyright 1988 by American Economic Association.

Zoltan J. Acs

Papers

Innovation and Small Firms

Innovation in Large and Small Firms: An Empirical Analysis

Local Geographic Spillovers between University Research and High Technology Innovations

Patents and innovation counts as measures of regional production of new knowledge

Innovation in Large and Small Firms: An Empirical Analysis