In data with a group structure, incidental parameters are included to control for missing variables. Applications include longitudinal data and sibling data. In general, the joint maximum likelihood estimator of the structural parameters is not consistent as the number of groups increases, with...

We examine the implications of arbitrage in a market with many assets. The absence of arbitrage opportunities implies that the linear functionals that give the mean and cost of a portfolio are continuous; hence there exist unique portfolios that represent these functionals. These portfolios span...

We consider linear predictor definitions of noncausality or strict exogeneity and show that it is restrictive to assert that there exists a time-invariant latent variable c such that x is strictly exogenous conditional on c. A restriction of this sort is necessary to justify standard techniques...

This paper is a re-examination of the relationship between research and development (R&D) activity and total factor productivity (TFP) at the industry level during the period extending from the early 1960's to the mid-1970's. The data base consists of NSF data on applied R&D expenditures by...

This paper presents the results of a study of productivity growth and R&D in the 1970s using data on narrowly defined 'business units within a firm. Estimates are developed under different assumptions about technology ,industry effects, and changes in the return to R&D over time. The R&D data...

This paper analyzes the relationship between output, employment, and physical and R&D capital, for a sample of 133 large U.S. firms covering the years 1966 through 197'.In the cross sectional dimension, there is a strong relationship between firm productivity and the level of its R&D...

In this paper we focus on alternative procedures for calculating and interpreting quality-adjusted price indexes for microcomputers, based on a variety of estimated hedonic price equations. Our data set comprises an unbalanced panel for 1265 model observations from 1982 to 1988, and includes...

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...

We present a model of endogenous firm growth with R&D investment and stochastic innovation as the engines of growth. The model for firm growth is a partial equilibrium model drawing on the quality ladder models in the macro growth literature, but also on the literature on patent races and the...

We present a model of endogenous firm growth with R&D investment and innovation as the engine of growth. The objective of our analysis is to present a framework that can be used for microeconometric analysis of firm performance in high-tech industries. The model for firm growth is a partial...