Zinaida Zugman

The Impact of Preventive Health Behaviour and Social Factors on Visits to the Doctor

BackgroundThe aim of this study is to examine the joint impact of preventive health behavior (PHB) and social and demographic factors on the utilization of primary and secondary medical care under a universal health care system, as measured by visits to the doctor, who were categorized as either a General Practitioner (GP) or Specialist Doctor (SD).MethodsAn ordered probit model was utilized to analyze data obtained from the 2009 Israeli National Health Survey. The problem of endogeneity between PHB factors and visits to GP was approached using the two-stage residuals inclusion and instrumental variables method.ResultsWe found a positive effect of PHB on visits to the doctor while the addition of the PHB factors to the independent variables resulted in important changes in explaining visits to GP (in values of the estimates, in their sign, and in their statistical significance), and only in slight changes for visits to SD. A 1% increase in PHB factors results in increasing the probability to visit General Practitioner in the last year in 0.6%. The following variables were identified as significant in explaining frequency of visits to the doctor: PHB, socio-economic status (pro-poor for visits to GP, pro-rich for visits to SD), location (for visits to SD), gender, age (age 60 or greater being a negative factor for visits to GP and a positive factor for visits to SD), chronic diseases, and marital status (being married was a negative factor for visits to GP and a positive factor for visits to SD).ConclusionsThere is a need for allowing for endogeneity in examining the impact of PHB, social and demographic factors on visits to GP in a population under universal health insurance.For disadvantaged populations with low SES and those living in peripheral districts, the value of IndPrev is lower than for populations with high SES and living in the center of the country. Examining the impact of these factors, significant differences in the importance and sometimes even in the sign of their influence on visits to different categories of doctors - GP and SD, are found.

Evaluating Innovations in the Ornamental Fish Industry

Abstract The ornamental fish industry has a number of characteristics that must be taken into account when suggesting a method for evaluating innovations at the farm level. A small model discus, Symphysodon aequifasciata, farm (high-value, low-volume egg-layers) served as the case study for this article. Innovations target such technological parameters as annual reproduction per pair, egg fertility, larval survival, and growth. The methods employed in this study involved the following steps: (a) building an operational model; (b) parameterization of the domain of all possible production plans, based on an innovation index c; (c) tabulation of an objective function fτ; (d) analysis of unit-free measures of economic response to innovations-point and arc elasticities of approximated fτ and identification of innovation stages by their response to increase in c. Numerical modeling (steps a, b, c) showed that improvement of larval survival allows an increase in net present value, which is several times larger than that effected by the other parameters tested. Three stages of innovation are identified in step d. A sharp decrease in elasticity at stage C indicates that further technological improvement cannot be economically efficient under limited aquarium volume. The method can be used to evaluate innovations for other farm types and other varieties of ornamental fish, both livebearers and egglayers.

Utilization of Primary and Secondary Medical Care among Disadvantaged Populations: A Log-Linear Model Analysis

Aim: We examined how, where an overall population is covered by universal health insurance, characteristics of disadvantaged populations interact to influence inequality in primary and secondary medical care utilization. Subject and Methods: Disadvantaged populations, the focus of the study, were defined as populations who have lower socio-economic status (SES), who are elderly and/or reside in a peripheral area. Data from the 2009 Israeli National Health Survey were analysed using log-linear models to estimate utilization of medical care. Results: The main findings were: a) pro-poor utilization of primary medical care among elderly populations, with higher odds ratios for low SES populations in the periphery; (b) lack of interaction between SES and primary medical care utilization among younger populations, between SES and secondary medical care utilization among the elderly and pro-rich utilization of secondary medical care among younger populations who did not regularly visit general practitioners (GP); (c) the odds ratios of secondary medical care utilization increased as SES decreased for both elderly and younger populations who also regularly visited a GP. Conclusion: Potential policy implications for disadvantaged populations, regarding possible inequality in primary and secondary medical care utilization, can be drawn using log-linear model analysis of interactions among characteristics (SES, age, location) of disadvantaged populations.

A Model for Estimating How Variability of Biological Parameters Affects Economic Factors in an Integrated Turkey Farm

Turkeys, as well as other poultry meat, are marketed as a healthier alternative to red meat. At the same time, the necessary investment in integrated turkey projects is 65% higher than for similar broiler projects. This explains the importance of rigorous evaluation of new turkey farms, including their sensitivity to biological parameters. We present a method of evaluating poultry projects that takes simultaneous variability of several biological parameters into account, using a bio-economic model, stochastic simulation, and an integrated turkey farm in Russia as a real-life example. The algorithm based on the Cholesky decomposition of the covariance matrix was used to generate a multivariate normal random vector of biological parameters. The bio-economic model takes into account simultaneous variability of major input biological parameters related to all stages of an integrated poultry farm: survival, hatchability, ratio of carcass weight to live weight, and number of eggs per layer. The highest variability of the output economic indices was estimated for internal rate of return: the coefficient of variation (CV) of this major economic index was approximately 240% of the CV of the input biological parameters. Such estimation can be used to analyze a projects economic risks, i.e., variability in production cost and profitability.

Avoiding economic losses by proper segregation of apples based on maturity indicators prior to storage

Abstract Economic losses resulting from inadequate segregation of fruit for different periods of storage in the packinghouse lead to decreased revenue for the farmer and increased costs to the packinghouse. This paper proposes an operationally practical decision-making procedure for apple segregation prior to storage based on maturity indicators, and taking into account the capacity of the packinghouse facilities. A segregation criterion is proposed to transform the quantity of apple needed to fill storage rooms into maturity restrictions, on the basis of information available in real time prior to storage. The calculation of maturity restrictions is based on a short-term prediction of maturity indicators. The loss function, presented in an “all-or-nothing” form, is utilized to compare the economic efficiency of the decision-making procedure for different methods of prediction and for present practice of apple segregation by the “first in–last out” rule. A simulation model is used for numerical realization of the proposed method of apple segregation with industrial data.

Lognormal Distribution of Apples in Relation to Maturity Restriction at Harvest

A model linking maturity indicators and the restrictions they impose on the apple yield assigned to a long-term storage (AppleLS) was studied. Using a three-step approach “maturity restrictions – parameterization - empirical distribution functions”, parameters of theoretical distributions for fitting AppleLS were estimated. Packinghouse data for three varieties over five years was used to building separate models for three periods of harvest. Normal and lognormal fits to empirical distribution functions of AppleLS were tested. A good agreement between the empirical distribution functions and their lognormal fits (high p-values for test) was observed in all studied cases. The established lognormal character of the distribution of fruit quantity in relation to maturity restrictions at harvest can be applied to modeling the quality of fruit handled in packinghouses.