Patterns of technology life cycles: stochastic analysis based on patent citations

Patent analysis has been considered as an effective means of estimating phases of a technology life cycle. However, previous studies have not considered the dynamic and idiosyncratic aspects of a technology’s progression since they were based on deterministic methods, mainly fitting s- or double s-shaped curves to patent application counts. Moreover, previous methods cannot be executed at the individual patent level. We propose a stochastic technology life cycle analysis to trace the phases of a technology’s progression based on patent citations and identify the patterns of technology life cycles at the individual patent level. At the heart of the proposed approach are a hidden Markov model to estimate the probability of a system being at a certain hidden state from observation and cluster analysis to group a set of objects according to their similarities. A case study of patents about laser technology in lithography is presented.     

Explorations - Introduction: Towards Lesbian,Gay, and Bisexual Perspectives in Economics: Why and How They May Make a Difference

The economics profession has only recently begun to include research on lesbians and gay men, but we argue that a lesbian economics has long existed, with documentation of anti-lesbian discrimination, discussion of its private and social costs, and practical work for change. This tradition, along with the newer traditions built upon work with gay men and bisexual people, provides a basis for feminists to expand work in economics on lesbian and gay issues. The articles in the symposium propose ideas for future research, for learning from other disciplines, and for creating a more welcoming academic climate.     

Does a Nearby Murder Affect Housing Prices and Rents? The Case of Sydney

We measure the impact of murders on prices and rents of homes in Sydney. We find that housing prices fall by 3.9 per cent for homes within 0.2 miles of the murder in the year following the murder, and weaker results in the second year after a murder. We do not find any effects of murders on rents. Higher media coverage and being located closer to the murder (within 0.1 mile) have no additional effect on prices. Taken together, our findings suggest that proximity to a murder affects nearby property prices, particularly in the first year after the incident.     

Time-varying relationship of news sentiment,implied volatility and stock returns

I examine the relationship between aggregate news sentiment, S&P 500 index (SPX) returns, and changes in the implied volatility index (VIX). I find a significant negative contemporaneous relationship between changes in VIX and both news sentiment and stock returns. This relationship is asymmetric whereby changes in VIX are larger following negative news and/or stock market declines. Vector autoregression (VAR) analysis of the dynamics and cross-dependencies between variables reveals a strong positive relationship between previous and current period changes in implied volatility and stock returns, while current period and lagged news sentiment has a significant positive (negative) relationship with stock returns (changes in VIX). I develop a simple trading strategy whereby high (low) levels of implied volatility signal attractive opportunities to take short (long) positions in the underlying index, while extremely negative (positive) news sentiment signals opportunities to enter short (long) index positions. The investor fear gauge (VIX) appears to perform better than news sentiment measures in forecasting future returns.     

Plea bargaining: on the selection of jury trials

We consider a model of the criminal court process, focusing on plea bargaining. A plea bargain provides unequal incentives to go to trial because innocent defendants are more willing to plead not guilty. We show that the court process implements the preferences of the person or group who is most concerned about wrongful conviction. If a prosecutor is more concerned about wrongful conviction than the jury, the prosecutor can shape the defendant pool at trial so that jurors act according to prosecutor’s preferences against judicial mistakes. Our model also connects insights from strategic jury models that usually omit plea bargaining with the actual criminal court process where most cases are resolved through plea bargaining. As an example, we show that the inferiority of the unanimity rule established in Feddersen and Pesendorfer (Am Polit Sci Rev 92(1):23–35, 1998) persists in spite of the addition of plea bargaining.     

On a family of data-based transformed models useful in forecasting technological substitutions

This paper examines, via real data, some well known models for technology substitution analysis. We propose a family of data-based transformed models that will include the models under examination as special cases. The basic thrust of the paper is the recognition that for technology substitution analysis, the observations are time series data and hence are not independent. Also, the functional form of the model should be determined by both theoretical considerations as well as the data on hand. This suggests that the traditional ordinary least squares procedure used in estimating the parameters and the resulting forecasting procedures are not adequate. The existing models examined here are Fisher–Pry, Gompertz, Weibull, and Normal. We stress the statistical aspects of the models and their relative merits in terms of predictive power. The criteria used for the purpose of comparison are the mean squared deviation and the mean absolute deviation of the predicted values compared with the actual observations.     

An alternative approach for portfolio performance evaluation: enabling fund evaluation relative to peer group via Malkiel’s monkey

We propose an implementable portfolio performance evaluation procedure that compares a portfolio with respect to the portfolios constructed by an infinite number of Malkiel’s blindfolded monkeys, or equivalently the whole enumeration of all possible portfolios. We argue that this approach exhibits two main advantages. First, it does not require any benchmark portfolios because a portfolio is being compared to an infinite number of portfolios. Second, it is market condition invariant. Since the market conditions are already reflected in the portfolio performances of an infinite blindfolded monkeys, our measure of portfolio performances is invariant to volatile market conditions.     

THE TIMING OF SIGNALING: TO STUDY IN HIGH SCHOOL OR IN COLLEGE?*

American students study harder in college than in high school, whereas East Asian students study harder in high school than in college. This article proposes a signaling explanation. Signaling may occur over time both in high school and in college, and societies may differ in the timing of signaling. Students work harder in the signaling stage determined by the society as a whole. A testable implication is that high ability workers in East Asia are more concentrated among a few colleges than their U.S. counterparts. This implication is confirmed by top CEO education profile data in the United States and Korea.