Bias in transition-specific survival and movement probabilities estimated using capture-recapture data

Transition probabilities can be estimated when capture-recapture data are available from each stratum on every capture occasion using a conditional likelihood approach with the Arnason-Schwarz model. To decompose the fundamental transition probabilities into derived parameters, all movement probabilities must sum to 1 and all individuals in stratum r at time i must have the same probability of survival regardless of which stratum the individual is in at time i + 1. If movement occurs among strata at the end of a sampling interval, survival rates of individuals from the same stratum are likely to be equal. However, if movement occurs between sampling periods and survival rates of individuals from the same stratum are not the same, estimates of stratum survival can be confounded with estimates of movement causing both estimates to be biased. Monte Carlo simulations were made of a three-sample model for a population with two strata using SURVIV. When differences were created in transition-specific survival rates for survival rates from the same stratum, relative bias was <2% in estimates of stratum survival and capture rates but relative bias in movement rates was much higher and varied. The magnitude of the relative bias in the movement estimate depended on the relative difference between the transition-specific survival rates and the corresponding stratum survival rate. The direction of the bias in movement rate estimates was opposite to the direction of this difference. Increases in relative bias due to increasing heterogeneity in probabilities of survival, movement and capture were small except when survival and capture probabilities were positively correlated within individuals.     

Cross-cultural issues in illness and wellness: Implications for depression

This paper addresses cultural factors in illness and wellness, using depression as a specific context. The issue of cultural relativism and commensurability of diagnosis and evaluation of outcomes across cultures is discussed. The concepts underlying traditional systems of healing are compared to those of Western orthodox medicine.     

Statistical approaches for the reliability of structural designs

The Construction Industry Research and Information Association (CIRIA) has produced some guidelines for the assessment of the reliability of components and/or structures. The methods of analysis suggested by these guidelines are far from adequate and, in certain cases, contain some imperfections. In this paper, some of the weaknesses of the guidelines are identified. The shortcomings are mainly in the ease of calculations and the feasibility of the assumptions which are imposed. Three alternative methods aimed at tackling some of the weaknesses are introduced. A simulation study is used to compare these methods.     

Modelling age variation in survival and reporting rates for recovery models

In this paper, we focus on models for recovery data from birds ringed as young. In some cases, it is important to be able to include in these models a degree of age variation in the reporting probability. For certain models this has been found, empirically, to result in completely flat likelihood surfaces, due to parameter redundancy. These models cannot then be fitted to the data, to produce unique parameter estimates. However, empirical evidence also exists that other models with such age variation can be fitted to data by maximum likelihood. Using the approach of Catchpole and Morgan (1996b), we can now identify which models in this area are parameter-redundant, and which are not. Models which are not parameter-redundant may still perform poorly in practice, and this is investigated through examples, involving both real and simulated data. The Akaike Information Criterion is found to select inappropriate models in a number of instances. The paper ends with guidelines for fitting models to data from birds ringed as young, when age dependence is expected in the reporting probability.     

BALANCED DESIGNS FOR ROW-AND-COLUMN EXPERIMENTS WITH TWO NON-INTERACTING SETS OF TREATMENTS, ONE SET NOT BEING APPLIED TO ALL THE ROWS1

This note gives and discusses balanced row-and-column designs for experiments with two non-interacting sets of treatments, one set not being applied to all the rows. These designs are potentially useful for occasions when trees that have tested one set of experimental treatments are needed for testing a second set before the residual effects of the first have become negligible, but when the experimenter wishes to apply the second set to only some of the rows. The designs are appropriate if the residual and new effects do not interact.     

EVIDENCE ON ELECTORAL ACCOUNTABILITY IN THE U.S. SENATE: ARE UNFAITHFUL AGENTS REALLY PUNISHED?

Many have questioned whether voters are able to hold incumbent officials electorally accountable through a retrospective voting strategy. We examine U.S. Senate elections from 1962 to 1990 in forty-one states, explaining which incumbents ran for reelection and their success in seeking reelection. We find that an incumbent's deviation from her state party platform decreases the probability that she will run for reelection and win if she runs. Furthermore, the electoral mechanism is found to be more efficient when voters are better informed. Finally, we find that our divergent party platform model provides a better fit than the median voter model.     

Rural Community Satisfaction and Attachment in Mass Consumer Society1

Abstract Previous models of community satisfaction and attachment have not included personal economic attitudes and behaviors as independent variables. Their inclusion is theoretically justified when residents of communities are viewed as consumers in a larger social/economic context first and residents of a particular community second. As locally-oriented economic processes—once part of the community experience—were removed to nonlocal markets, local economic and demographic attributes became less important to rural residents' experience of community. In two rural communities with extreme scores on a service center viability index, satisfaction with employment and location of employment are important predictors.