Inference of non-centrality parameter of a truncated non-central chi-squared distribution

Non-central chi-squared distribution plays a vital role in statistical testing procedures. Estimation of the non-centrality parameter provides valuable information for the power calculation of the associated test. We are interested in the statistical inference property of the non-centrality parameter estimate based on one observation (usually a summary statistic) from a truncated chi-squared distribution. This work is motivated by the application of the flexible two-stage design in case–control studies, where the sample size needed for the second stage of a two-stage study can be determined adaptively by the results of the first stage. We first study the moment estimate for the truncated distribution and prove its existence, uniqueness, and inadmissibility and convergence properties. We then define a new class of estimates that includes the moment estimate as a special case. Among this class of estimates, we recommend to use one member that outperforms the moment estimate in a wide range of scenarios. We also present two methods for constructing confidence intervals. Simulation studies are conducted to evaluate the performance of the proposed point and interval estimates.     

Intention to emigrate in transition countries: the case of Albania

We analyse the profile of potential emigrants from Albania using data from the Central and Eastern Europe Eurobarometer in 1992. Respondents were asked to rate on a four-point scale the likelihood that they would go to live in Western Europe. Our results show that intention to emigrate is correlated positively with males, education and certain occupations, and negatively with age. There is little relation between emigration and income. Those who support the introduction of a free market in Albania are also more likely to emigrate than those who do not. Received: 24 August 1998/Accepted: 17 April 2000     

Threshold Estimation for Stochastic Processes with Small Noise

Consider a process satisfying a stochastic differential equation with unknown drift parameter, and suppose that discrete observations are given. It is known that a simple least squares estimator (LSE) can be consistent but numerically unstable in the sense of large standard deviations under finite samples when the noise process has jumps. We propose a filter to cut large shocks from data and construct the same LSE from data selected by the filter. The proposed estimator can be asymptotically equivalent to the usual LSE, whose asymptotic distribution strongly depends on the noise process. However, in numerical study, it looked asymptotically normal in an example where filter was chosen suitably, and the noise was a Lévy process. We will try to justify this phenomenon mathematically, under certain restricted assumptions.     

Exponentially weighted moving average charts for correlated multivariate Poisson processes

In this article, we study exponentially weighted moving average (EWMA) control schemes to monitor the multivariate Poisson distribution with a general covariance structure, so that the practitioner can simultaneously monitor multiple correlated attribute processes more effectively. The statistical performance of the charts is assessed in terms of the run length properties and compared against other mainstream attribute control schemes. The application of the proposed methods to real-life and simulated datasets is demonstrated.     

Rank and response: A field experiment on peer information and water use behavior

Perception of peer rank, or how we perform relative to our peers, can be a powerful motivator. While research exists on the effect of social information on decision making, there is less work on how ranked comparisons with our peers influence our behavior. This paper outlines a field experiment conducted with 3896 households in Castro Valley, California, which uses household mailers with various forms of social information and peer rank messaging to motivate water conservation. The experiment tests the effect of a visible peer rank on water use, and how the competitive framing of rank information influences behavioral response. The results show that households with relatively low or high water use in the pre-treatment period responded differently to how rank information was framed. I find that a neutrally-framed peer rank caused a small “boomerang effect” (i.e., an increase in average water use) for low water use households, but this effect was eliminated by competitive framing. At the same time, a competitively-framed peer rank demotivated high water use households, increasing their average water use over the full period of the experiment. This result is supported by evidence that the competitive frame on rank information increased water use for households who ranked “last” in the peer group – a detrimental “last place effect” from competitively-framed rankings.     

Exploitation aversion: When financial incentives fail to motivate agents

Studies of the principal-agent relationship find that monetary incentives work in many instances but that they can also backfire. Various mechanisms for this failure have been examined (e.g., intrinsic motivation, image concerns). We posit that an aversion to being exploited, i.e., being used instrumentally for another’s benefit, can also cause incentives to fail. Using an experiment we find that compliance is lower for exploitative principals compared to neutral ones despite using the same contracts. To corroborate our results we show that surveyed “exploitation aversion” mediates this effect. Our results have implications for the design and implementation of incentives within organizations.     

Rent-seeking and competitive preferences

In this experiment, I examine the extent to which competitive social preferences can explain over-bidding in rent-seeking contests. The Human treatment is a standard two-player contest. In the Robot treatment, a single player bids against a computerized player, eliminating potential social preference motives. The results show no difference in bids between treatments at the aggregate level. Further analysis shows evidence of heterogeneous treatment effects between impulsive and reflective subjects. Moreover, impulsive subjects are more likely than reflective subjects to deviate qualitatively from the shape of the theoretical best response function.     

Reconsidering the philanthropic foundation minimum payout policy under a “new normal”

With the increasing salience of foundations in many policy fields, and recent changes in market conditions, policies towards foundations designed decades ago seem outdated. In this article we suggest reassessing foundation payout minimums. To examine the impact of payout rates on grantmaking foundations lifespan and performance under “new normal” economics, we simulate multiple foundations lifecycles using Monte Carlo methods in diverse capital market conditions, with varied investment and payout strategies.We find that while under past market regime perpetuity seems to be a given, under more probable future scenarios, foundations might face increasingly early mortality and endowment depletion, limiting their potential impact. Furthermore, lower payout rates allow for higher lifetime grantmaking, higher mean annual grantmaking, and lower giving volatility. Accordingly, we suggest a tiered payout policy, in line with foundations’ missions and proper financial planning.     

The relationship between conflict events and commodity prices in Sudan

Though recent literature uncovers linkages between commodity prices and conflict, the causal direction of the relationship remains ambiguous. We attempt to contribute to this strand of research by studying the dynamic relationship of commodity prices and the onsets of conflict events in Sudan. Using monthly data ranging from January 2001 through December 2012, we identify a structural breakpoint in the multivariate time series model of prices of the three staple foods (sorghum, millet, and wheat) and conflict measure (number of conflict events) in September of 2011. Applying structural vector autoregression (SVAR) and linear non-Gaussian acyclic model (LiNGAM), we find that wheat price fluctuation is a root cause of conflict events in Sudan. We recommend several policy and programmatic suggestions structured toward production, subsidy, price regulation and support for rural farmers and consumers to stabilize commodity prices.