Learning About Computers: An Analysis of Information Search and Technology Choice

We estimate a dynamic model of how consumers learn about and choose between different brands of personal computers (PCs). To estimate the model, we use a panel data set that contains the search and purchase behavior of a set of consumers who were in the market for a PC. The data includes the information sources visited each period, search durations, as well as measures of price expectations and stated attitudes toward the alternatives during the search process. Our model extends recent work on estimation of Bayesian learning models of consumer choice behavior in environments characterized by uncertainty by estimating a model of active learning—i.e., a model in which consumers make optimal sequential decisions about how much information to gather prior to making a purchase. Also, following the suggestion of Manski (2003), we use our data on price expectations to model consumers’ price expectation process, and, following the suggestion of McFadden (1989a), we incorporate the stated brand quality information into our likelihood function, rather than modeling only revealed preference data.Our analysis sheds light on how consumer forward-looking price expectations and the process of learning about quality influence the consumer choice process. A key finding is that estimates of dynamic price elasticities of demand exceed estimates that ignore the expectations effect by roughly 50%. This occurs because our estimated expectations formation process implies that consumers expect mean reversion in price changes. This enhances the impact of a temporary price cut. Finally, while our work focuses specifically on the PC market, the modeling approach we develop here may be useful for studying a wide range of high-tech, high-involvement durable goods markets where active learning is important.JEL Classification: C15, C33, C35, C42, C51, C52, D83, D84     

Share Tipsters and Fair Advertising

The paper considers the concept of ‘fairness' as it applies to the advertisements of investment advisers. In the light of the empirical evidence relating to the performance of investment tipsters and fund managers, it is argued that current advertising practices tend to raise investors’ expectations to unrealistic levels. Possible changes to advertising practice regulations are considered.     

Changes in the structure of earnings during the Polish transition

We document changes in the structure of earnings during the economic transition in Poland. We find that inequality in labor earnings increased substantially from 1988 to 1996. A common view is that the reallocation of workers from a public sector with a compressed wage distribution, to a private sector with much higher wage inequality, accounts for the bulk of increased earnings inequality during transition (see, e.g., the models of Aghion and Commander (1999) [Aghion, Philippe, Commander, Simon, 1999. On the dynamics of inequality in the transition. Economics of Transition 7, 275–2898.] and Commander and Tolstopiatenko (1998) [Commander, Simon, Tolstopiatenko, Andrei, 1998. The role of unemployment and restructuring in the transition. In: Commander, Simon (Ed.), Enterprise Restructuring and Unemployment in Models of Transition. The World Bank, Washington, pp. 169–192.]). However, our decomposition of the sources of the increase in inequality suggests that this compositional effect accounts for only 39% of the increase. Fully 52% of the increase is due to the increase in the variance of wages within sectors. That is, earnings inequality within both the private and public sectors grew substantially, and by similar amounts. This is consistent with prior work suggesting that even state-owned enterprises in Poland moved towards competitive wage setting as they restructured (see, e.g., Pinto et al. (1993) [Pinto, Brian, Belka, Marek, Krajewski, Stefan, 1993. Transforming state enterprises in Poland: evidence on adjustment by manufacturing firms. Brookings papers on Economic Activity, 213-70.] Commander and Dhar (1998) [Commander, Simon, Dhar, Sumana, 1998. Enterprises in the Polish transition. In Simon Commander (Ed.), Enterprise Restructuring and Unemployment in Models of Transition. The World Bank, Washington, pp. 109-142.]).A substantial part of the increase in earnings inequality was between group, due largely to increased education premiums. However, changes in inequality within education–experience–gender groups account for about 60 percent of the increase in overall earnings inequality. The increases in within-group inequality were very different across skill groups, with much larger increases for highly educated workers. These patterns hold in both the private and public sectors, although increases in education premiums were somewhat greater in the private sector.     

ANOMALOUS BIDDING IN SHORT‐TERM TREASURY BILL AUCTIONS*

We show that Treasury bill auction procedures create classes of price‐equivalent discount rates for bills with less than 72 days to maturity. We argue that it is inefficient for market participants to bid at a discount rate that is not the minimum rate in its class. The inefficiency of bidding at other than the minimum rate is related to a quantity shortfall rather than an unexploited profit opportunity. Auction results for weekly offerings of four‐week bills and occasional offerings of cash management bills show that market participants frequently bid at inefficient rates. However, they are more likely to bid at efficient rates than chance would suggest.     

A central limit theorem for sums of correlated products

Consider a sequence of random points placed on the nonnegative integers with i.i.d. geometric (1/2) interpoint spacings y _i . Let x _i denote the numbers of points placed at integer i . We prove a central limit theorem for the partial sums of the sequence x ₀ y ₀, x ₁ y ₁, . . . The problem is connected with a question concerning different bootstrap procedures.     

Health care spending and hidden poverty in India

India has a high level of out-of-pocket (OOP) health care spending, and lacks well developed health insurance markets. As a result, official measures of poverty and inequality that treat medical spending symmetrically with consumption goods can be misleading. We argue that OOP medical costs should be treated as necessary expenses for the treatment of illness, not as part of consumption. Adopting this perspective, we construct poverty and inequality measures for India that account for impoverishment induced by OOP medical costs. For 2011/12 we estimate that 4.1% of the population, or 50 million people, are in a state of “hidden poverty” due to medical expenses (based on official poverty lines). Furthermore, while poverty in India fell substantially from 1999/00 to 2011/12, the fraction of the remaining poverty that is due to medical costs has risen substantially. Economic growth appears less “pro-poor” if one accounts for OOP medical costs, especially since 2004/05, and especially in rural areas. Finally, we look beyond poverty rates to show how OOP health costs affect the entire shape of the consumption distribution.     

Behavioral frontiers in choice modeling

We review the discussion at a workshop whose goal was to achieve a better integration among behavioral, economic, and statistical approaches to choice modeling. The workshop explored how current approaches to the specification, estimation, and application of choice models might be improved to better capture the diversity of processes that are postulated to explain how consumers make choices. Some specific challenges include how to capture and parsimoniously describe heterogeneous mixes of heuristic choice rules, methods for building realistic models of choice, and nontraditional methods for estimating models. An agenda for important future work in these areas is also proposed.     

A COMPUTATIONALLY PRACTICAL SIMULATION ESTIMATION ALGORITHM FOR DYNAMIC PANEL DATA MODELS WITH UNOBSERVED ENDOGENOUS STATE VARIABLES*

This article develops a simulation estimation algorithm that is particularly useful for estimating dynamic panel data models with unobserved endogenous state variables. Repeated sampling experiments on dynamic probit models with serially correlated errors indicate the estimator has good small sample properties. We apply the estimator to a model of female labor supply and show that the rarely used Polya model fits the data substantially better than the popular Markov model. The Polya model also produces far less state dependence and many fewer race effects and much stronger effects of education, young children, and husband's income on female labor supply decisions.