Population Estimation Methods Research Articles

地域間比較のためのリスク人口の推定方法―インフルエンザ定点報告数に関する分析―

This study proposes a risk population estimation method based on the reported counts of patients of influenza in each area. A risk population estimation method is developed by regarding the sum of the weekly observations in a season following the binomial distribution, which enables estimations of population parameters and probability parameters through maximum likelihood method. The results show that the estimated infection probability is consistently correlated with population density, and the estimated population parameters in areas with high populations are obviously small in comparison with the proportion of population.

Population Estimation Methods in GIS and Remote Sensing: A Review

This paper reviews existing population estimation methods in the GIS and remote sensing literatures. The methods can be grouped into two categories: areal interpolation methods and statistical modeling methods. Areal interpolation methods can be further separated into two categories depending on whether ancillary information is used. Statistical modeling methods can be further grouped into five categories based on the relationship between populations and urban areas, land uses, dwelling units, image pixel characteristics, or other physical or socioeconomic characteristics.

ANNUAL VARIATION IN POPULATION ESTIMATORS FOR A SOUTHERN POPULATION OF AMBYSTOMA MACULATUM

For six breeding seasons (1997–2002), we conducted an intensive mark-recapture study on a breeding population of the spotted salamander, Ambystoma maculatum, near the southern edge of their range in east-central Alabama. A drift fence completely encircling an ephemeral pond was used to capture all adult salamanders migrating into or out of the pond, and passive integrated transponders were used to provide individual identification. The Jolly-Seber method of population estimation was used to estimate three population parameters (size, gains, and survivorship); population growth rate was also estimated. Gains varied annually, ranging from 24 ± 16 to 101 ± 24, and population growth rate was low (r = 0.18 ± 0.188), suggesting inconsistent recruitment. Consistent with life history parameters of long-lived, late-maturing species, survivorship (range 0.629 ± 0.064 to 0.699 ± 0.08) and breeding population sizes (range 189 ± 24 to 260 ± 16) remained essentially constant. The demographics for A. maculatum provided by this study are useful for planning conservation initiatives.

Application of remote sensing technology to population estimation

This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density) method and model method, incorporating the application experience of American scholars in the light of the state of our country. Firstly, the author proposes theoretical basis for population estimation by remote sensing, on the basis of analysing and evaluating the history and state quo of application of methods of population estimation by remote sensing. Secondly, two original types of mathematical models of population estimation are developed on the basis of remote sensing data, taking Tianjin City as an example. By both of the mathematical models the regional population may be estimated from remote sensing variable values with high accuracy. The number of the independent variables in the latter model is somewhat smaller and the collection of remote sensing data is somewhat easier, but the deviation is a little larger. Finally, some viewpoints on the principled problems about the practical application of remote sensing to population estimation are put forward.

A preliminary comparison of population estimation by tape response and mark/recapture methods for Storm Petrels Hydrobates pelagicus in two contrasting Scottish colonies

The tape response method of population estimation was compared to mark/recapture methods for Storm Petrels Hydrobates pelagicus on two Scottish islands. On Priest Island the du Feu single‐session mark/recapture method gave an estimate not significantly different from the tape response method and was less demanding on personnel. On Eilean Hoan the Jolly‐Seber estimates made in 1998 and 1999 were similar to that obtained from the tape response method in 2001. Jolly‐Seber estimates made in 2000 and 2001 were similar to the du Feu estimate made in 2001, but different from the tape response method. The overall annual survival estimate of 0.87 on Eilean Hoan was identical to the previously published figure and almost the same as the 0.86 calculated from national ringing returns. These initial findings are used to identify problems with the mark/recapture methods and to suggest ways of solving them.

Comparison of methods to estimate weed populations and their performance in yield loss description models

Accurate weed population estimation and yield loss prediction are important components of integrated weed management. Field experiments using Italian ryegrass as a weed in broccoli were conducted from 1994 to 1997 to compare weed density to other methods of weed population estimation, to evaluate the performance of weed population estimates in yield description models, and to study the affect of environmental variability on the predictive ability of models. A strong linear relationship was obtained between Italian ryegrass density and direct leaf area (r2 = 0.60 to 0.99). For Italian ryegrass, density and estimates of canopy from the optical device (crosswire device) had a hyperbolic relationship with high coefficients of determination (r2 > 0.72). Both direct leaf area and canopy estimates described broccoli yield as well as or better than Italian ryegrass density. The Li-Cor LAI-2000 Plant Canopy Analyzer (PCA) provided poor estimates of Italian ryegrass population (r2 from 0.00 to 0.63) that failed to describe broccoli yield. No relationship was observed between estimates of light interception through the plant canopy obtained with the Li-Cor LI-191-S Line Quantum Sensor (LQS) and either Italian ryegrass density or broccoli yield. The low performance of the PCA and lack of performance of the LQS were likely due to the smaller size of the plants and larger gaps in the plant canopy caused by wide bed spacing. At similar densities, Italian ryegrass competition with broccoli was stable from year to year. Under high Italian ryegrass density, water supply affected competition. This may limit construction of robust yield prediction models, especially in areas where water is mainly from rainfall.

The Fish Community of a Small Impoundment in Upstate New York

ABSTRACT Moe Pond is a dimictic impoundment with surface area of 15.6 ha, a mean depth of 1.8 m, and an unexploited fish community of only two species: brown bullhead (Ameiurus nebulosus) and golden shiner (Notemigonus crysoleucas). The age-1 and older brown bullhead population was estimated to be 4,057 individuals, based on the Schnabel capture-recapture method of population estimation. Density and biomass were respectively estimated at 260 individuals/ha and 13 kg/ha. Annual survival rate of age-2 through age-5 brown bullheads was estimated at 48%. The golden shiner length-frequency distribution was unimodal with modal length of 80 mm and maximum total length of 115 mm. The golden shiner population estimate was 7,154 individuals, based on seven beach seine haul replicate samples; the density and biomass were 686 shiners/ha and 5 kg/ha, respectively. This study provides an information baseline that may be useful in understanding food web interactions and whole-pond nutrient flux.

Use of mark-recapture techniques to estimate the size of hard-to-reach populations.

To review the main problems associated with mark-recapture methods of population estimation, and to indicate some practical strategies for addressing these problems, with illustrations from a study of drug-use prevalence across Wales. Unnamed identifier data were collected in 1994 on 2610 drug users who were in contact with various agencies across Wales: the police, drug treatment agencies, needle exchanges, probation services, and agencies reporting to the Welsh Drugs Misuse Database. Based on the dependency relationships between different agencies' datasets, different estimates of the 'hidden' populations (not in contact with agencies) were modelled for each county, for males and females, for injecting drug users and serious drug users, and for those under 25 and those over 25 years of age. Different models were also constructed for the same subpopulations, using different agency datasets and different criteria of overlap between them, yielding a total of 230 different models. The issues of sample heterogeneity and population definition are particularly intractable in mark-recapture studies. Sample heterogeneity may be partly addressed by separately modelling different subpopulations to check whether they show the same dependency relationships as the main population. Population definition may be partly addressed by restricting modelling to datasets thought to share roughly congruent population definitions.

Indirect prevalence estimates of a national drug using population: The use of contact-recontact methods in Wales

The changing discourses of risk entail more than shifts in cosmologies of misfortune: they also embrace technical changes in risk surveillance. Public health medicine has sought estimates of drug-using populations to plan drug services and to interpret data on the prevalence of infectious diseases. Concealment of risk behaviours had led to technical advances in indirect methods of population estimation, one such method being that of contact-recontact, where the size of the hidden population (unknown to agencies) is estimated by modelling the dependency relationships (the overlaps) between different agenices lists of clients. This study demonstrates the use of contact-recontact methods for estimating the national prevalence of serious drug use, a procedure only previously attempted for city-wide populations of drug users. Three- and four-sample contact-recontact models have been used and log linear regression techniques have been applied to assess dependencies between datasets. Results from the modelling exercise provide an estimate for serious drug use in Wales in 1994 of 8384 people (95% C.I. 5307-11 407). This gives a rate per thousand population of 2.87 (95% C.I. 1.8-3.9) and 5.34 (95% C.I. 3.4-7.3) per thousand aged 15-55. Prevalence estimates are also provided for former Welsh counties by age and sex. Prevalence estimates for injecting drug use are provided for a smaller number of former counties in Wales. Methodological problems have been encountered (and variously addressed) in respect of varying agency definitions of clients, matching definitions and availability of datasets.

Restoration of Insular Ecosystems: Control of Feral Goats on Aldabra Atoll, Republic of Seychelles

The control of feral goats (Capra hircus) was studied on Aldabra Atoll, Republic of Seychelles, from October 1993 to May 1994 and November 1994 to May 1995. A total of 832 goats was killed on Aldabra using the Judas goat technique and traditional hunting methods. Twenty-eight goats equipped with radio transmitters (Judas goats) were used to locate and kill other feral goats. The remnant goat populations on Ile Picard (n=13) and Ile Malabar (n=19) were eradicated during the first season. On Grande Terre, a total of 798 (374 M : 424 F) goats were killed. Mean group size was 3.2 with a range of 1–20. Judas goat hunting became increasingly important over time with 18.0% (n=85) of goats killed in the presence of Judas goats in the first season compared to 42.3% (n=126) of goats killed during the second season. The overall kill rate for the project was almost 2 times greater for Judas goat hunting (0.61 goats killed/h) than traditional hunting (0.32 goats killed/h). The home range size of each Judas goat and the number of goats killed in association with it was significantly related. Using the Leslie–Davis removal method of population estimation, 84 goats were estimated to remain on all of Grande Terre at the end of thebreak project.

Depletion as a Technique to Estimate Commercial Pond Inventories of Channel Catfish

Abstract A depletion population estimation method was tested in three trials in experimental ponds and in 19 commercial ponds that held channel catfish Ictalurus punctatus. Estimates of population numbers in experimental ponds differed from measured population numbers by +6.5%, −3.8%, and −18.4%, respectively. Estimates of population weights differed from measured population weights by −0.1%, 0%, and −7.7%, respectively. Estimated population numbers in two commercial ponds in 1995 differed from measured population numbers by −0.3% to −2.4%, and estimated population weights differed from measured population weights by −3.5% to −6.1%. In 1996, depletion estimates of population weight from 17 commercial channel catfish ponds differed from measured weights by −1.4 ± 13.7%. A fourth sampling point (tested in five commercial ponds) did not significantly (P ≥ 0.05) improve the accuracy of population estimates. The depletion method appears to have potential as an alternative management tool that could be used per...

Linking substance and practice: a case study of the relationship between socio-economic structure and population estimation 1

Population estimation methods designed for the state/provincial and county levels generally exhibit high levels of accuracy. However there are persistent shortcomings that have not been resolved through methodological development. We argue that at least some of these shortcomings would be better understood by linking these methods with the substantive socio-economic and demographic dynamics that clearly must be underlying the changes in population that the methods are designed to measure. To illustrate our main point we conduct a case study of Indiana over two periods 1970-1980 and 1980-1990. Indiana is selected because a common population estimation method exhibits a common problem over the two periods: its coefficients change. We link these changes to Indianas transition to a post-industrial economy and describe how this transition operated through demographic dynamics that ultimately affected the estimation model. (EXCERPT)

Ripeness effects of three vegetable crops on abundance of augmentatively released psyttalia fletcheri (Hym.: Hraconidae): Improved sampling and release methods

Studies were done to determine the effect of 4 fruit ripeness levels on the abundance of Psyttalia fletcheri (Silvestri),a parasitoid of Bactrocera cucurbitae (Coquillett). In addition,an improved trapping method was developed for monitoring massreleased adult parasitoids in the field. A total of 420,000 adult P. fletcheri were released over a period of 15 weeks,in a 0.16 ha experimental field plot containing cucumber,zucchini and tomato in Kauai,HI. We recovered significantly more P. fletcheri from rotting fruits of all fruit types than from immature,commercial grade or oversized fruits. In addition,there was a positive correlation between the number of P. fletcheri and B. cucurbitae recovered from rotting fruits. Average parasitism in rotting tomato,zucchini and cucumber was 5,19 and 36% respectively. Yellow pan traps were as effective as sticky sphere traps for monitoring P. fletcheri,indicating that parasitoids were foraging close to the ground where rotting fruits occurred. The pan traps were much easier to use,less expensive and required less set up time. Recovery of parasitoids from both fruit collections and pan traps indicated that P. fletcheri was least abundant in tomato. Both male and female parasitoids exhibited a weakly aggregated distribution in each crop. We discuss modified sampling and release methods for population estimation and augmentative release studies of P. fletcheri.

Chapter 17 Estimation and use of Kinetic Parameter Distributions in Metabolism and Nutrition

This chapter discusses the estimation, and the use of kinetic parameter distributions in metabolism and nutrition. The chapter reviews the theory, applications, and available software, with particular attention to how they relate to problems in metabolism and nutrition. The population estimation methods developed by pharmacokineticists to handle sparse data have potential use in the data-rich studies encountered in metabolism and experimental nutrition. They provide a consistent and logical method to combine information from several experiments, accounting for interindividual variation in a theoretically sound manner. Anyone working in kinetic analysis should be aware of these tools, their advantages, and their limitations. The population methods avoid making assumptions about missing data by simultaneously considering all the experiments in a rigorous and consistent way. Although the mathematics is the same, kinetic modeling in metabolism and experimental nutrition differs from pharmacokinetics. It is the responsibility of the user to be aware of identifiability issues.

The effect of undercount on the accuracy of small-area population estimates: Implications for the use of administrative data for improving population enumeration

The effects of underenumeration on the accuracy of alternative methods of population estimation have not been sufficiently analyzed. Although the US Bureau of the Census has decided not to adjust either the counts or its estimates for underenumeration in 1990, the extent to which local population estimates may account for underenumeration is of importance both for those who may wish to adjust existing estimates and in anticipation of future census adjustments. This paper examines the accuracy of small-area population estimation methods with and without adjustment. Mean Percent Errors, Mean Absolute Percent Errors, and Mean Percent Absolute Differences between local estimates for 1990 and 1990 adjusted and unadjusted census counts are computed. Population estimates for 1990 made using housing unit, ratio correlation, and component methods are compared for 451 counties and 2,633 places in the states of California, Florida, Texas, and Wisconsin. An analysis of the data for counties shows little indication that local estimates more accurately estimate the adjusted than the unadjusted population counts. The results for places show clear improvements in accuracy for places in Florida and Texas. Implications of the findings for issues related to undercount adjustment and local population estimates are discussed.

Influence of Guava Ripening on Parasitism of the Oriental Fruit-Fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), by Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) and Other Parasitoids

Abstract The effects of guava ripening on abundance and parasitism rates of parasitoids of oriental fruit fly, Bactrocera dorsalis (Hendel), were determined in three guava ( Psidium guajava L.) orchards. Diachasmimorpha longicaudata (Ashmead) was released in Kilauea, Kauai, and Waiakea, Hawaii. Natural densities of this parasitoid were measured in a third orchard in Panaewa, Hawaii. Fruits ripening on the tree and the ground after abscission of fruit were classified into four categories, ranging from to mature-green to rotten fruit. The egg parasitoid, Biosteres arisanus (Sonan) was the dominant parasitoid emerging from tree-harvested guavas at all sites and composed 90-98% of all parasitoids recovered but decreased in abundance as guava fruit aged on the ground. In all three orchards, D. longicaudata increased in abundance and parasitism rates were highest in guavas that remained on the ground for 6-10 days. Consequently, the impact of this parasitoid is usually underestimated by sampling commercially ripe guava fruit from the tree or freshly fallen fruit on the ground. The eulophid parasitoid, Tetrastichus giffardianus (Silvestri), was more abundant in 4- to 9-day-old ground fruit. We discuss modified sampling methods for population estimation and augmentative release studies of parasitoids of oriental fruit fly.

Evaluating the Housing Unit Method: A Case Study of 1990 Population Estimates in Florida

Abstract The housing unit (HU) method is the most commonly used approach to making small-area population estimates in the United States. This study evaluates the accuracy and bias of HU population estimates produced for counties and subcounty areas in Florida for April 1, 1990. The major findings are that population size has a negative effect on estimation errors (disregarding sign) but no effect on bias; growth rates have a U-shaped effect on estimation errors (disregarding sign) and a negative effect on bias; electricity customer data provide more accurate household estimates than do building permit data; errors in household estimates contribute more to population estimation error than do errors in estimates of average household size or group quarters population; and the application of professional judgment improves the accuracy of purely mechanical techniques. We believe the HU method offers a number of advantages over other population estimation methods and provides planners and demographers with a powerful tool for small-area analysis.

Markov‐Recapture Population Estimate: A Tool for Improving Interpretation of Trapping Experiments

This paper describes a method of population estimation in which a random, unknown number of individuals is marked using a self—marking bait station (a trap modified for mark and release); animals (both marked and unmarked) may then be captured in an otherwise identical trap, which is available simultaneously. The estimate of the unknown population size is based on the assumption of a closed population and a simple Markov model in which the rates of marking and capture are assumed to be equal. The population size estimator is based on the maximum likelihood technique, and is given by the nest integer less than N = (C + R)2/2(R + 1), where R and C are, respectively, the numbers of marked and unmarked individuals found in the trap. The estimator is almost unbiased for a wide range of true population sizes, and over a wide range of times over which the experiment is run, although it becomes negatively biased when the mean number of recaptures is <5. Confidence limits may be obtained using asymptotic maximum likelihood arguments, although relative likelihood methods perform better when the number of recaptures is small.

A New Short-Term County Population Projection Method1

This paper proposes a new method for short-term county population projections. It is based on a modification of the ratio-correlation method of population estimation. The modified ratio-correlation method can produce projections with a high potential for accuracy without requiring substantial data and intensive intellectual labor inputs. Tests of accuracy are examined for the modified ratio-correlation method and two currently available alternatives using data from Washington state. The tests suggest that the new method performs well. (EXCERPT)

Estimating the Population Prevalence of Injection Drug Use and Infection with Human Immunodeficiency Virus among Injection Drug Users in Glasgow, Scotland

Although data on the prevalence of injection drug use are an essential prerequisite for estimating the number of individuals infected with the human immunodeficiency virus (HIV), there have been few attempts to utilize statistical methods of population estimation based on multiple data sources. Data on 3,670 cases (2,866 individuals) were obtained from the HIV test register, drug treatment agencies, police records, and needle and syringe exchanges in Glasgow, Scotland, in 1990. Log-linear analysis was used to model the number of individuals in each of the sources. The model incorporating dependency among the three health care agencies (HIV test, drug treatment, and needle exchange) and independence of the police sample fitted the data well, with a residual chi 2 value of 2.9 (6 df). The expected value of the missing cell corresponding to absence from all four samples was 5,628, yielding an overall estimate of 8,494 injectors (95% confidence interval (CI) 7,491-9,721), for a prevalence rate of 1.35% for people aged 15-55 years in Glasgow during 1990. The high ratio of known to unknown injectors (1:2) resulted from the extensive coverage of known injectors and the relatively high level of overlap between the combined health care agency sample and the police sample. While further analysis demonstrated that the probability of appearing in the four samples varied by age and sex, heterogeneity in the population did not affect the choice of model or substantially alter the estimates for the total number of unknown injectors. A concurrent study of a community-wide sample of 503 injectors resulted in an HIV prevalence rate of 1.1% (95% CI 0.4-2.5%). The results of these studies were combined to produce a further estimate of 93 HIV-infected current injectors in Glasgow (95% CI 33-214).