Using patent citation data for the U.S., we test whether knowledge spillovers in biotechnology are sensitive to distance, and whether that sensitivity has changed over time. Controlling for self-citation by inventor, assignee and examiner, cohort-based regression analysis shows that physical distance is becoming less important for spillovers with time.
Network analysis shows a stable network between states, but a changing environment between individual actors, with a growing importance of connectedness. The popular maxim that everyone is connected by six degrees of separation is tested with surprising results.
Although previous empirical studies have found relationships between patent characteristics and value, none have determined how specific attributes relate to auction value or even the probability of a successful auction sale. Using a Heckman two-step model, we regress thirteen independent variables against unique patent auction data, finding that publicly-owned and frequently referenced patents are more valuable, and that other things equal, there is an optimal time to offer a patent up for auction.
This study shows how social capital affects the outreach and operational self-sufficiency of microfinance institutions (MFIs) around the world. Defining social capital as social networks, social norms, and trustworthiness, this research merges quantitative data from the Microfinance Information Exchange and World Values Survey to empirically test a which aspects of social capital have the greatest influence on MFI performance in the presence of an endogenous peer effect between MFIs. Regression results show that aspects of social capital have a direct influence on MFI performance, suggesting a tradeoff between outreach and sustainability, and display a strong endogenous peer effect.
This paper evaluates the contribution of patent-related events to changes in stock prices, proposing that economics has traditionally failed to find much effect for two reasons which we identify and correct. First, patents vary widely in quality so we use quantile analysis and alternative measures of patent quality to identify effects. Second, we permit the possibility that information leaks out into investor sentiment during the long and uncertain time until patent grant, so evaluate the stock price effect at four different dates in the life of each patent. As a case study to test this approach, track all patents over a 27-year period for Apple Inc., permitting design patents to have different effects that traditional utility-model patents, and isolate the effect that Steve Jobs’s name on a patent has at each stage of a patent’s life.
We model the diffusion of economic knowledge using an epidemiological model of susceptible, exposed, infected, and recovered populations (SEIR). Treating bibliographic citations as evidence of contagion, we estimate the coefficients of a four-equation system simultaneously for each of 759 subfields of economics. Results show that some subfields grow endogenously much faster than others, and just over half have basic reproduction properties sufficient to ensure survival without the annual addition of new protégé scholars.
In 2006, philanthropic giving to higher education institutions totaled $28 billion, with the top school receiving just under a billion dollars. Roughly fifteen percent of those funds came from alumni donations. This paper builds upon existing economic models to create an econometric model predicting the ever-more important pattern of alumni giving. We test the model using data from over 22,000 alumni at a private liberal arts college, and report on the probable profiles for annual fund donors and alumni willing and able to give major gifts.
Agriculture, like many primary and service sectors, is a frequent recipient of innovation intended for its use, even if those innovations originate in industrial sectors. The challenge has been identifying them from patent data, which are recorded for administrative purposes using the International Patent Classification (IPC) system. We reprogram a well-tested tool, the OECD Technology Concordance (OTC), to identify 16 million patents granted between 1975 and 2006 worldwide which have potential application in agriculture. This paper presents the methodology of that dataset’s construction, introduces the data via summaries by nation and industrial sector over time, and suggests some potential avenues for future exploration of empirical issues using these data.
This paper tests the induced innovation hypothesis that higher oil prices will lead to increased innovation in energy-efficient automotive technology. We find robust empirical support for the hypothesis, while using various measures of oil and gas prices and controlling for other factors including constructed knowledge stocks and macroeconomic variables.
While there is anecdotal evidence that home values decline when a big-box store (such as Wal-Mart) decides to locate in the area, there is a paucity of evidence on that effect. This paper uses a repeat sales model to compare residential property values, and the speed of sale of the property, to compare the impact that an arrival has. Results conclude that there is a "news effect" surrounding the arrival, and that the total effect is small at most. For most specifications tested, the number of stores nearby, the arrival of new stores, and the distance to the nearest store all have insignificant impacts on both property resale value and the number of days that a property spends on the market prior to sale. In the worst-case scenario, the arrival of a Wal-Mart is associated with a decline equivalent to roughly one percent of the home's square footage and is not absorbed by those closest to the new retailer but by rather more distant neighbors.