Indirect Estimation Techniques Research Articles

Estimation and Projection of Fertility in Nepal

The text discusses the importance of indirect estimation techniques in understanding population dynamics, particularly in countries with limited or flawed data like Nepal. Indirect methods offer valuable insights into fertility and mortality rates when direct measures are unavailable or unreliable. Techniques like Brass P/F ratio and the logistic curve function are explored for estimating fertility trends and projecting Total Fertility Rates (TFR). These methods involve meticulous analysis and adjustment for data inconsistencies. Indirect estimation plays a crucial role in bridging data gaps and informing demographic analysis and planning, especially in regions undergoing demographic transition. Through these techniques, researchers gain valuable insights into fertility dynamics, contributing to a better understanding of population trends. The text explores fertility estimation in Nepal using Arriaga's method, analyzing data from the 2011 and 2021 censuses. It reveals disparities in lifetime fertility indices, particularly after age 20, with higher rates among women aged 20-24 and 25-34, tapering towards the end of the reproductive span. Arriaga's adjustments address issues like misreporting of children's ages, aiming to rectify discrepancies and estimate the Total Fertility Rate (TFR) for both years. Additionally, the study discusses fertility projections for 2026 and 2031, highlighting the importance of trend extrapolation models and the logistic curve for accurate estimation. The findings underscore the significance of meticulous adjustments and reliable methodologies in understanding fertility dynamics in Nepal.

Direct Evidence of Bitcoin Wash Trading

We use the internal trading records of a major Bitcoin exchange leaked by hackers to detect and characterize wash trading—a type of market manipulation in which a single trader clears the trader’s own limit orders to “cook” transaction records. Our finding provides direct evidence for the widely suspected “fake volume” allegation against cryptocurrency exchanges, which has so far only been backed by indirect estimation. We then use our direct evidence to evaluate various indirect techniques for detecting the presence of wash trades and find measures based on Benford’s law, trade size clustering, lognormal distributions, and structural breaks to be useful, whereas ones based on power law tail distributions to give opposite conclusions. We also provide suggestions to effectively apply various indirect estimation techniques. This paper was accepted by Professor Bruno Biais, finance. Funding: J. Li acknowledges support by the U.S. Department of Homeland Security [Grant 205187] through the Criminal Investigations and Network Analysis Center. Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2021.01448 .

Mathematical Analysis of Fertility in Nepal Using Arriaga's Approach

This article has judged how well the P/F changing ratio technique and Arriaga's approach forecast fertility levels in Nepal. The study's goal was accomplished and the logistic curve function was legalized by estimating national fertility rates. Using information from the 2011 till 2021 censuses together with Arriaga's methodology, the following factual investigates the calculation of fertility rates in Nepal. By using cutting edge indirect fertility estimation techniques on a national level, this study seeks to evaluate the fertility change in Nepal. Utilizing information from the 2011 and 2021 Censuses, fertility estimates were produced with an emphasis on last-year births. The findings show that Nepal's fertility rates have recently dropped.   

Indirect estimation of pediatric reference interval via density graph deep embedded clustering

Establishing reference intervals (RIs) for pediatric patients is crucial in clinical decision-making, and there is a critical gap of pediatric RIs in China. However, the direct sampling technique for establishing RIs is resource-intensive and ethically challenging. Indirect estimation methods, such as unsupervised clustering algorithms, have emerged as potential alternatives for predicting reference intervals. This study introduces deep graph clustering methods into indirect estimation of pediatric reference intervals. Specifically, we propose a Density Graph Deep Embedded Clustering (DGDEC) algorithm, which incorporates a density feature extractor to enhance sample representation and provides additional perspectives for distinguishing different levels of health status among populations. Additionally, we construct an adjacency matrix by computing the similarity between samples after feature enhancement. The DGDEC algorithm leverages the adjacency matrix to capture the interrelationships between patients and divides patients into different groups, thereby estimating reference intervals for the potential healthy population. The experimental results demonstrate that when compared to other indirect estimation techniques, our method ensures the predicted pediatric reference intervals in different age and gender groups are closer to the true values while maintaining good generalization performance. Additionally, through ablation experiments, our study confirms that the similarity between patients and the multi-scale density features of samples can effectively describe the potential health status of patients.

Evaluation of the influence of correcting for gillnet selectivity on the estimation of population parameters.

Gill nets are a common sampling technique in inland and marine fisheries. However, gill nets are size selective and may result in bias estimates of population parameters. As such, selectivity is commonly assessed using indirect estimation techniques. Indirect estimates of gillnet selectivity have been suggested to improve estimates of important populations metrics (e.g., total annual mortality), but this assertion has not been assessed. In the current study, we simulated hypothetical populations of channel catfish Ictalurus punctatus, lake trout Salvelinus namaycush, walleye Sander vitreus, and white crappie Pomoxis annularis and sampled the populations based on published gillnet encounter and retention probabilities. Total annual mortality and von Bertalanffy parameters were then estimated using unadjusted (not "correcting" for selectivity processes) and adjusted ("correcting" for selectivity processes) age and(or) length data to evaluate the value of accounting for gillnet selectivity when estimating these metrics. Our results indicate that adjusting for retention and encounter probabilities rarely leads to improved estimates of total annual mortality, K, and L∞. For instance, estimates of annual mortality of lake trout based on age data adjusted for retention probability resulted in an overestimate of A by 14.4%. As such, we suggest that analysis of gillnet selectivity only be used when specific questions are being addressed (e.g., catch-at-age models) or in situation when all processes contributing to gillnet selectivity (e.g., contact probability, size-specific availability) are known.

Indirect force estimation method under spectrally varying and amplitude-sensitive conditions by estimating the effective fluid path parameter

Indirect methods to estimate the force transmitted from the source to the receiver have been investigated using various approaches to increase accuracy and overcome discrepancies, especially when the measurements are conducted in situ. To implement the indirect force estimation techniques in situ, developing an accurate measurement method and establishing reasonable system models always matter when the force estimations involve nonlinear internal forces such as the upper chamber pressures of the hydraulic mount system. Based on prior research conducted on force estimation in a nonlinear hydraulic mount, a simplified reverse-path spectral method is proposed in this study for estimating the force transmitted from the driving point to the ground by focusing on one effective fluid path parameter. To achieve the purpose of this study, two interfacial force datasets from the non-resonant test were first captured along with spectrally varying and amplitude-sensitive conditions. Second, two different path forces were determined from the rubber and hydraulic paths, and the effective fluid path parameter (EFP) was estimated from the hydraulic path force. The employment of the EFP contributes to estimating the effective internal properties, which show better correlations with the measurements than the estimated results from prior studies. Thus, the current work, performed by focusing on the EFP, successfully suggests a simplified yet efficient way to develop an indirect force estimation method in a nonlinear hydraulic mount as a dynamic load sensing system.

Economic Growth in Germany, 1500–1850

New data are used to construct a time series of real GDP in Germany for the period 1500–1850 using an indirect output estimation technique that relies on wages, prices, and sectoral employment. Until the mid-seventeenth century, real GDP per capita moved inversely with population. The eighteenth century saw a modest rise in output per head. From the late 1810s, economic growth gradually accelerated. The results shed new light on the reversal of fortunes in early modern Europe and the transition from a Malthusian regime to modern economic growth.

Research on indirect measurement and estimation method of shearer drum cutting load

For the difficult problem that the shearer drum load is difficult to be detected and perceived directly, a shearer drum load indirect estimation measurement method and technique is proposed and invented. Based on the structural characteristics of the rocker arm, the basic rod system skeleton of the rocker arm is extracted. Based on the transfer route of the drum load on the rocker arm, the feasibility of using the rocker arm pin shaft load for drum load prediction is analyzed, and the correlation mechanics equation of load from the drum to the rocker arm pin shaft is constructed. To address the statically indeterminate problem in the equation, the Lagrange multiplier is introduced to construct the energy function of the rocker rod system skeleton. Based on the principle of minimum complementary energy and solving the extreme value of energy function, the statically indeterminate equation is transformed into the statically determinate equation, and a rough prediction model of drum load based on the force of the rocker arm hinged ear pin shaft is derived, and the maximum relative error of the model is 25.15 %. To address the low prediction accuracy of the model due to the dynamic characteristics of the drum rocker arm, the drum load is derived from the rocker arm hinged ear pin shaft load and the rough prediction model as input, and the experimentally measured drum load as output. The bp neural network error correction model is constructed, and the accurate estimation and perception of the drum load are realized by the prediction model and the bp neural network correction model. Finally, the accuracy of the prediction algorithm is verified by experiments. The results show that after correction by bp neural network, the average error of the drum three directional force is 0.14 × 104N ∼ 0.55 × 104N, the mean square error is 0.18 × 104N ∼ 0.65 × 104N, and the relative error is 3.99 %∼10.12 %. The average error of the drum three directional moment is 0.31 × 104N·m ∼ 0.40 × 104N·m, the mean square error is 0.16 × 104N·m ∼ 0.50 × 104N·m, and the relative error is 2.04 %∼11.44 %. The accuracy of drum load prediction is higher than 11.44 % in all cases. The research results can provide theoretical and technical support for intelligent shearer design, development, and healthy operation and maintenance.

Global Shocks in the US Economy: Effects on Output and the Real Exchange Rate

This paper studies the effects of global shocks, relative to domestic shocks (productivity, mark-up, and demand shocks), in accounting for US business cycle fluctuations. We do this by developing and estimating a two-sector open economy dynamic stochastic general equilibrium model that features several real frictions and structural shocks. The central finding from the estimated model is that global shocks are the main driver of movements in many US macroeconomic aggregates. Particularly, we find that they explain around 40% of the variations in our main variables of interest—output and real exchange rate. This important quantitative contribution is achieved by using indirect inference estimation techniques to test the model. We identify exogenous world demand, oil price shocks, preference for exported energy-intensive goods, and the price of imported energy-intensive goods as the global shocks most prominent in causing the largest variations in economic outcomes. By contrast, foreign interest rates and preference for aggregate exported goods are found to be bystanders.

An Assessment of Third-Party Reporting of Close Ties to Measure Sensitive Behaviors: The Confidante Method to Measure Abortion Incidence in Ethiopia and Uganda.

Indirect estimation techniques are important tools for measuring sensitive and stigmatized behaviors. This includes third‐party reporting methods, which have become increasingly common in the field of abortion measurement, where direct survey approaches notoriously lead to underreporting. This paper provides the first in‐depth assessment of one of the most widely used of these techniques in the field of abortion measurement: the confidante method. We outline six key assumptions behind the confidante method and describe how violations of these assumptions can bias resulting estimates. Using data from modules added to the performance monitoring for action surveys in Uganda and Ethiopia in 2018, we compute one‐year abortion incidence estimates using the confidante method. We also perform a validation check, using the method to estimate intrauterine device /implant use. Our results revealed implementation problems in both settings. Several of the method's foundational assumptions were violated, and efforts to adjust for these violations either failed or only partially addressed the resulting bias. Our validation check also failed, resulting in a gross overestimate of intrauterine device/implant use. These results have implications more broadly for the potential biases that can be introduced in using third‐party reporting of close ties to measure other sensitive or stigmatized behaviors.

Model Based Indirect Conicity Estimation Technique for Solid Axle Railway Wheelset

Conicity is an important characteristic that helps the railway vehicle to steer itself down the track. However during the operation, the conicity tends to change inconsistently due to frictional contact at the wheel-rail interface. Safety, reliability and ride comfort which are utmost importance for journey are adversely affected due to the changes in conicity level beyond certain limit. Several techniques have been employed for monitoring the health of the railway wheelset however still a significant potential exists to investigate the wheelset conicity. This paper presents a model based technique to monitor the wheelset condition which contributes to the wheel flats due to decrease in conicity level and the problem of false flanges due to increased level of conicity. In this paper an unconstrained solid axle railway wheelset is considered for study. The dynamic behavior of the wheelset is analyzed at different conicity levels to understand the effect of the conicity on the wheelset. In order to demonstrate the potential of this research work a simulation model is developed in Matlab/ Simulink to mimic the behavior of an actual wheelset. Simplified linearized model of the wheelset is used to estimate the dynamics of the wheelset. From the simulation results it is evident that the frequency of vibration is changing with the changes in conicity level. In this way using the proposed method the conicity level is indirectly identified. The results produced by simulation model are satisfactory.

Can Indirect Estimation Methods and the Medical Officer of Health Reports 'Correct' Distorted Infant Mortality Rates Reported by the Registrar General? The Case of London, 1896–1911

The Registrar General's Returns are an integral source for historical demographers. Concerns have been raised, however, over the geographical accuracy of their pre-1911 mortality figures when institutional deaths were not redistributed to place of residence. This paper determines the extent of the distortions caused by institutional mortality in the context of aggregate infant mortality rates for London's registration sub-districts. The potential of two alternative methods to 'correct' these distortions is then assessed. The first method uses indirect estimation techniques based on data from the 1911 Fertility Census, and the second exploits the rich detail available from the Medical Officer of Health reports. Through narrowing the focus to seven London registration sub-districts over the years 1896–1911, it is shown that both suggested alternative methods remove the institutional mortality biases found in the Registrar General's figures, yet they come with their own limitations.

Noninvasive intracranial pressure monitoring methods: a critical review.

Intracranial pressure (ICP) monitoring has been used for decades in management of various neurological conditions. The gold standard for measuring ICP is a ventricular catheter connected to an external strain gauge, which is an invasive system associated with a number of complications. Despite its limitations, no noninvasive ICP monitoring (niICP) method fulfilling the technical requirements for replacing invasive techniques has yet been developed, not even in cases requiring only ICP monitoring without cerebrospinal fluid (CSF) drainage. Here, we review the current methods for niICP monitoring. The different methods and approaches were grouped according to the mechanism used for detecting elevated ICP or its associated consequences. The main approaches reviewed here were: physical examination, brain imaging (magnetic resonance imaging, computed tomography), indirect ICP estimation techniques (fundoscopy, tympanic membrane displacement, skull elasticity, optic nerve sheath ultrasound), cerebral blood flow evaluation (transcranial Doppler, ophthalmic artery Doppler), metabolic changes measurements (near-infrared spectroscopy) and neurophysiological studies (electroencephalogram, visual evoked potential, otoacoustic emissions). In terms of accuracy, reliability and therapeutic options, intraventricular catheter systems still remain the gold standard method. However, with advances in technology, noninvasive monitoring methods have become more relevant. Further evidence is needed before noninvasive methods for ICP monitoring or estimation become a more widespread alternative to invasive techniques.

Signal Based Indirect Wheel Profile Estimation Technique for Solid Axle Railway Wheelset

Wheel profile is a very important factor that helps the steering performance of the railway vehicle. However, during the operation, the wheel profile tends to vary inconsistently due to frictional contact at wheel-rail interface. This paper focuses on the problem of railway wheelset profile and its alteration that affects the performance of railway vehicle. Signal-based indirect estimation technique using Fast Fourier Transform (FFT) is proposed to establish a relationship between dynamic response of vehicle and wheel profile. It is observed that changes in wheel profile has direct impact on the frequency of lateral dynamics. The effect of vehicle speed is also analyzed on the yaw and lateral motions of the wheelset. The effectiveness of the proposed technique in determining the relationship between the frequency of the oscillation and conicity level of the solid axle railway wheelset is demonstrated by developing simulation model in MATLAB and Simulink.

The Linear Link: Deriving Age-Specific Death Rates from Life Expectancy

The prediction of human longevity levels in the future by direct forecasting of life expectancy offers numerous advantages, compared to methods based on extrapolation of age-specific death rates. However, the reconstruction of accurate life tables starting from a given level of life expectancy at birth, or any other age, is not straightforward. Model life tables have been extensively used for estimating age patterns of mortality in poor-data countries. We propose a new model inspired by indirect estimation techniques applied in demography, which can be used to estimate full life tables at any point in time, based on a given value of life expectancy at birth. Our model relies on the existing high correlations between levels of life expectancy and death rates across ages. The methods presented in this paper are implemented in a publicly available R package.

Evaluation of the body adiposity index against dual-energy X-ray absorptiometry for assessing body composition in children and adolescents.

It is important to clarify the association of lean and fat mass between children and adolescents considering the rising prevalence of overweight and obesity in this age group. The aim of this study was to verify the association between the body adiposity index (BAI) and dual-energy X-ray absorptiometry (DXA) methods for analyzing body composition, as well as analyzing the validity of BAI to verify the percentage of fat in children and adolescents. The sample was composed of 106 children and adolescents, 44 females (age: 11.5± 1.8 years) and 62 evils (13.6± 2.6 years). The body fat (%F) was measured using DXA and the doubly indirect BAI body fat estimation technique. The BAI and DXA estimates of %F were strongly correlated (boys: r=.71, P<.0001; girls: r=.72, P<.0001). The linear regression analyses showed that BAI is significant to estimate the %F in total sample (P<.0001). For boys, the %F analyzes performed by BAI and DXA did not show any differences when compared (P=.2). In addition, BAI pointed out a significant proportion bias for both sexes (P<.0001), which suggests its inefficiency in the analysis of %F. BAI and DXA correlate; however, there is low reliability and a high proportion bias for the analysis of %F by BAI.

International Migration and City Growth in the Global South: An Analysis of IPUMS Data for Seven Countries, 1992–2013

AbstractEvidence on the demographic components of city growth in the global South is scarce, and the role played by international migration is neglected. We analyze the importance of recent international migration in cities, compare it with that of internal movements, and evaluate the growth contribution across national contexts and the urban hierarchy. Combining individual‐level census data and geographic master files of metropolitan areas with indirect demographic estimation techniques, we cover 377 cities in seven countries. It is found that, in almost one third of cities, population change and replacement has been mainly determined by migration. The international component was larger than the internal one in more than half of cities. Whereas internal migration tends to decrease with rising city size, international movements tend to increase. Positive net international migration substitutes for the net losses from domestic movements in large cities, but complements the gains in intermediate‐sized cities.

Estimation of tensile strength of sandy soil from soil–water characteristic curve

During heavy rainfalls, the surface soil on a slope may be eroded and the erosion is much dependent on the tensile strength of soil. In addition, the tensile strength of soil is also one of the governing factors which affect the cracking of soil. It is noted that the water content of soil has a significant effect on the tensile strength of soil. The experimental works for measurement of the tensile strength of soil in laboratory (especially for the unsaturated soil) are challenging, and the indirect estimation techniques draw a lot of attentions among practical engineers. In this paper, the tensile strength of soil is estimated from the soil–water characteristic curve (SWCC) by adopting the concept of pore-size distribution function. The proposed equations were verified with the experimental data from published literature. The comparison results show that the estimated tensile strengths agree well with the experimental results of the selected soils from published literatures. In addition, the variations of SWCC due to different initial densities and fine contents are also considered and the effects of the variation of SWCC on the estimated tensile strength are also investigated and discussed in this paper. It is observed that the modified SWCCs incorporating the effects of different initial densities and fine contents are able to provide a more accurate estimation of the tensile strength of unsaturated soil.

Trends in maternal and neonatal mortality in South Africa: a systematic review.

BackgroundMeasuring and monitoring progress towards Millennium Development Goals (MDG) 4 and 5 required valid and reliable estimates of maternal and child mortality. In South Africa, there are conflicting reports on the estimates of maternal and neonatal mortality, derived from both direct and indirect estimation techniques. This study aimed to systematically review the estimates made of maternal and neonatal mortality in the period from 1990 to 2015 in South Africa and determine trends over this period.MethodsNationally-representative studies reporting on maternal and neonatal mortality in South Africa were included for synthesis. Literature search for eligible studies was conducted in five electronic databases: Medline, Africa-Wide Information, Scopus, Web of Science and CINAHL. Searches were restricted to articles written in English and presenting data covering the period between 1990 and 2015. Reference lists of retrieved articles were screened for additional publications, and grey literature was searched for relevant documents for the review. Three independent reviewers were involved in study selection, data extractions and achieving consensus.ResultsIn total, 969 studies were retrieved and 670 screened for eligibility yielding 25 studies reporting data on maternal mortality and 14 studies on neonatal mortality. Most of the studies had a low risk of bias. Estimates from the institutional reporting differed from the international metrics with wide uncertainty/confidence intervals. Moreover, modelled estimates were widely divergent from estimates obtained through empirical methods. In the last two decades, both maternal and neonatal mortality appear to have increased up to 2009, followed by a decrease, more pronounced in the care of maternal mortality.ConclusionEstimates from both global metrics and institutional reporting, although widely divergent, indicate South Africa has not achieved MDG 4a and 5a goals but made a significant progress in reducing maternal and neonatal mortality. To obtain more accurate estimates, there is a need for applying additional estimation techniques which utilise available multiple data sources to correct for underreporting of these outcomes, perhaps the capture-recapture method.Systematic review registrationPROSPERO CRD42016042769

A Comparison of Methods for Poverty Estimation in Developing Countries

SummarySmall area estimation is a widely used indirect estimation technique for micro‐level geographic profiling. Three unit level small area estimation techniques—the ELL or World Bank method, empirical best prediction (EBP) and M‐quantile (MQ) — can estimate micro‐level Foster, Greer, &amp; Thorbecke (FGT) indicators: poverty incidence, gap and severity using both unit level survey and census data. However, they use different assumptions. The effects of using model‐based unit level census data reconstructed from cross‐tabulations and having no cluster level contextual variables for models are discussed, as are effects of small area and cluster level heterogeneity. A simulation‐based comparison of ELL, EBP and MQ uses a model‐based reconstruction of 2000/2001 data from Bangladesh and compares bias and mean square error. A three‐level ELL method is applied for comparison with the standard two‐level ELL that lacks a small area level component. An important finding is that the larger number of small areas for which ELL has been able to produce sufficiently accurate estimates in comparison with EBP and MQ has been driven more by the type of census data available or utilised than by the model per se.