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Cluster Sampling (cluster + sampling)
Kinds of Cluster Sampling Terms modified by Cluster Sampling Selected AbstractsThe Use of Cluster Sampling to Determine Aid Needs in Grozny, Chechnya in 1995DISASTERS, Issue 3 2000Sean Drysdale War broke out in Chechnya in November 1994 following a three-year economic blockade. It caused widespread destruction in the capital Grozny. In April 1995 Medical Relief International - or Merlin, a British medical non-governmental organisation (NGO) - began a programme to provide medical supplies, support health centres, control communicable disease and promote preventive health-care in Grozny. In July 1995 the agency undertook a city-wide needs assessment using a modification of the cluster sampling technique developed by the Expanded Programme on Immunisation. This showed that most people had enough drinking-water, food and fuel but that provision of medical care was inadequate. The survey allowed Merlin to redirect resources earmarked for a clean water programme towards health education and improving primary health-care services. It also showed that rapid assessment by a statistically satisfactory method is both possible and useful in such a situation. [source] Ratio estimators in adaptive cluster samplingENVIRONMETRICS, Issue 6 2007Arthur L. Dryver Abstract In most surveys data are collected on many items rather than just the one variable of primary interest. Making the most use of the information collected is a issue of both practical and theoretical interest. Ratio estimates for the population mean or total are often more efficient. Unfortunately, ratio estimation is straightforward with simple random sampling, but this is often not the case when more complicated sampling designs are used, such as adaptive cluster sampling. A serious concern with ratio estimates introduced with many complicated designs is lack of independence, a necessary assumption. In this article, we propose two new ratio estimators under adaptive cluster sampling, one of which is unbiased for adaptive cluster sampling designs. The efficiencies of the new estimators to existing unbiased estimators, which do not utilize the auxiliary information, for adaptive cluster sampling and the conventional ratio estimation under simple random sampling without replacement are compared in this article. Related result shows the proposed estimators can be considered as a robust alternative of the conventional ratio estimator, especially when the correlation between the variable of interest and the auxiliary variable is not high enough for the conventional ratio estimator to have satisfactory performance. Copyright © 2007 John Wiley & Sons, Ltd. [source] The epidemiological aspects of irritable bowel syndrome in Southeastern Anatolia: a stratified randomised community-based studyINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2005erif Yilmaz Summary Even though studies on the epidemiology of the irritable bowel syndrome (IBS) are increasing day by day, epidemiological data are still unknown in many regions. Our objective was to determine the IBS prevalence, factors associated with this prevalence and probable risk groups in Southeastern Anatolia. The total population in the target region is approximately 6 million. A total of 3000 people (1521 females and 1479 males) randomly selected by stratified cluster sampling were interviewed face-to-face by using a questionnaire comprising demographic features and the Rome II criteria which also included probable risk factors and questions related with Bristol scale stool form. The statistical analysis was performed by using a package program called epi info 2000. IBS prevalence was 10.2% according to the Rome II criteria in our region. Six hundred and twenty-five of 3000 subjects had gastrointestinal symptoms in the last 3 months. IBS rate was higher in women (12.4%) than in men (8.0%), and married subjects had higher IBS rates (11.6%) than singles (6.7%). Those differences were statistically significant (p = 0.000 for both). It was most common in the 35,54-year age group. No difference was observed in terms of settlement (rural/urban), age group, education and occupation. History of abortion in women increased the IBS risk by 1.8 times (p = 0.000 Crude odds ratios = 1.8 (1.3,2.6) 95% confidence intervals). Of the IBS patients, 48.1% had characteristics of diarrhoea-predominance, 38.9% constipation-predominance while 13.0% had none. There was a significant relation between dominant stool form and Bristol scale stool form. IBS prevalence is 10.2% in the first community-based study carried out in this specific subject in Southeastern Anatolia. The dominance of middle age and females remained significant. [source] Seniors' attitudes: oral health and quality of lifeINTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 1 2004Audrey Penner Abstract:, The objective of this study was to determine what impact, if any, oral health was having on the quality of life for selected seniors in Prince Edward Island, Canada. The attitudes of seniors towards oral health and its relationship to quality of life is important to define. This self-reported assessment provides information on this particular relationship. The research design was a random cluster sampling that covered all geographical areas of Prince Edward Island. It represented the cultural diversity within these geographical areas. The survey instrument selected was the Subjective Oral Health Indicators' Status, a validated survey instrument. This particular instrument addressed all the issues raised in the objectives. Data were analysed using Pearson's correlation with age and number of teeth present. The independent t -test was used to identify differences in responses by gender. Results of the survey showed identification of individual indicators that were having an impact on quality of life. Gender differences in responses were identified in four of the eight subject areas. The level of worry/concern was inconclusive because of the high non-response rate to the last question. Non-response rates increased with each topic in the questionnaire. More research is needed to identify clinical needs of seniors on Prince Edward Island. Qualitative study to determine attitudes and beliefs could provide groundwork for future programme design. [source] Nursing research in Spain: bibliometrics of references of research papers in the decade 1985,1994JOURNAL OF ADVANCED NURSING, Issue 6 2001Carmen Pardo Nursing research in Spain: bibliometrics of references of research papers in the decade 1985,1994 Background.,Spain is one of the few European countries to have recently totally incorporated the study of nursing into the university sector. Bibliometric studies may be of a great help for the consolidation of nursing research. Aim of the study.,The aim of this paper is to describe bibliographic references in Spanish nursing research papers and their evolution over a decade. Method.,The method consists of a retrospective bibliometric study of a sample (cluster sampling) of 622 research papers (original papers and review papers), which were contained in the Spanish nursing journals Enfermería Científica, Revista ROL de Enfermería, Enfermería Clínica and Enfermería Integral, and published from 1985 to 1994. The journal Nursing Research was selected for qualitative comparative purposes. A series of classic bibliometric indexes were used. Results.,The mean of references per paper is 10·64 ± 10·42; this increased over time (P < 0·001). Review papers have more references (P < 0·001). Price index (percentage of references published during the last 5 years) is 44% and the Insularity (percentage of references published in same country as the article) is 55%. References to journals predominate (58·6%), with a growing tendency for references to Spanish nursing journals, although they are still scarce (18·1% of the references to journals). Spanish is the language of most of the references (60·3%), the second language being English (36·1%). Conclusions.,Bibliographic references in Spanish nursing research papers are scarce and not very specific: this happens both in regard to Nursing Research and to publications in other national and international science areas. However, there is an increasing tendency of references (including references to nursing journals) in the period analysed. The age of the references places Spanish nursing in an intermediate position between the ,hard' sciences and the humanities; and, according to the type of documentation used, we find it halfway between experimental and natural sciences, and technologies and social sciences. There has been a slight increase in references in English in recent years. [source] Sampling survey on intellectual disability in 0,6-year-old children in ChinaJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 12 2008Z.-H. Xie Abstract Objectives To understand the current status of intellectually disabled children and the prevalence of intellectual disability (ID) in children aged 0,6 years and its risk factors, and to provide scientific evidence to formulate relevant policies for helping intellectually disabled children. Methods Multiphase, stratified, unequal proportional and cluster sampling was adopted to investigate 60 124 children aged 0,6 years. All the children investigated were screened for ID using the Denver Developmental Screening Test, and those with positive screening test would be further diagnosed by varied specialists using the Gesell Developmental Inventory. Results In total, 560 of 60 124 children were diagnosed as intellectually disabled with an overall prevalence of 0.93%. Prevalence of ID was highest in children living in medium-developed areas with a prevalence of 1.20%, higher than in those living in developed areas (0.75%) and in underdeveloped areas (0.84%). It was higher in rural areas (1.03%) than in urban areas (0.83%), and higher in boys (1.01%) than in girls (0.84%). Prevalence of ID increased with the age of children and decreased with the educational level of their parents. Conclusions The study suggested that ID is still prevalent in the children of China, and rehabilitation for them is lagging behind current needs. Early prevention of ID in children and pre-school education for them should be strengthened. [source] The association between clinical oral health status and oral impacts experienced by older individuals in Sri LankaJOURNAL OF ORAL REHABILITATION, Issue 9 2004L. Ekanayake summary, The aim of this study was to determine the association between clinical oral status and oral impacts experienced by older individuals in Sri Lanka. A total of 585 individuals who were above 60 years and were residents of an urban area was selected using a multistage cluster sampling combined with probability proportionate to size technique. However the present analysis is limited to 235 individuals who were subjected to a clinical oral examination. An interviewer administered Sinhala translation of the Oral Health Impact Profile-14 (OHIP-14) scale was used to assess the oral impacts experienced by the sample. An oral examination was carried out following the interview. Of the 235 subjects clinically examined 64 (27%) were edentulous. The associations between clinical parameters and oral impacts were assessed in the 171 dentate subjects. There were positive, weak but significant correlations between the number of missing teeth, the number of teeth with third degree mobility and the OHIP score. Also those who wore dentures and had halitosis had significantly higher OHIP scores than those who did not wear dentures and did not have halitosis. Logistic regression analysis revealed that ,wearing denture' and ,having halitosis' were significant predictors of the OHIP score. In conclusion, there was a weak association between clinical parameters and oral impacts experienced by these older individuals. [source] Improved unbiased estimators in adaptive cluster samplingJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 1 2005Arthur L. Dryver Summary., The usual design-unbiased estimators in adaptive cluster sampling are easy to compute but are not functions of the minimal sufficient statistic and hence can be improved. Improved unbiased estimators obtained by conditioning on sufficient statistics,not necessarily minimal,are described. First, estimators that are as easy to compute as the usual design-unbiased estimators are given. Estimators obtained by conditioning on the minimal sufficient statistic which are more difficult to compute are also discussed. Estimators are compared in examples. [source] A population-based epidemiologic study of irritable bowel syndrome in South China: stratified randomized study by cluster samplingALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 11 2004L. S. Xiong Summary Background :,The detailed population-based data on irritable bowel syndrome in South China are lacking. Aims :,To assess the prevalence of irritable bowel syndrome in South China and its impact on health-related quality of life. Subjects and methods :,A face-to-face interview was carried out in South China to assess the prevalence of irritable bowel syndrome. Random clustered sampling of permanent inhabitants aged 18,80 years was carried out under stratification of urban and suburban areas. The impact of irritable bowel syndrome on health-related quality of life was evaluated using the Chinese version of SF-36. Results :,A total of 4178 subjects (1907 male and 2271 female) were interviewed. The adjusted prevalence of irritable bowel syndrome in South China is 11.50% according to the Manning criteria and 5.67% according to the Rome II criteria. Factors including history of analgesic use such as non-steroidal anti-inflammatory drug (odds ratio 3.83), history of food allergies (odds ratio 2.68), psychological distress (odds ratio 2.18), life events (odds ratio 1.89), history of dysentery (odds ratio 1.63) and negative coping style (odds ratio 1.28) were significantly associated with the presence of irritable bowel syndrome (P < 0.05). Irritable bowel syndrome was significantly associated with a decrement in health-related quality of life score. Conclusion :,Irritable bowel syndrome is a common disorder in South China and has a negative impact on health-related quality of life. [source] A Review of the Cluster Survey Sampling Method in Humanitarian EmergenciesPUBLIC HEALTH NURSING, Issue 4 2008Shaun K. Morris ABSTRACT Obtaining quality data in a timely manner from humanitarian emergencies is inherently difficult. Conditions of war, famine, population displacement, and other humanitarian disasters, cause limitations in the ability to widely survey. These limitations hold the potential to introduce fatal biases into study results. The cluster sample method is the most frequently used technique to draw a representative sample in these types of scenarios. A recent study utilizing the cluster sample method to estimate the number of excess deaths due to the invasion of Iraq has generated much controversy and confusion about this sampling technique. Although subject to certain intrinsic limitations, cluster sampling allows researchers to utilize statistical methods to draw inferences regarding entire populations when data gathering would otherwise be impossible. [source] Risk factors for sebaceous gland diseases and their relationship to gastrointestinal dysfunction in Han adolescentsTHE JOURNAL OF DERMATOLOGY, Issue 9 2008Hong ZHANG ABSTRACT Sebaceous gland diseases are a group of common dermatological diseases with multiple causes. To date, a systematic report of the risk factors for sebaceous gland diseases in adolescents has not been published. The aim of this study was to assess the prevalence and risk factors for certain sebaceous gland diseases (seborrhea, seborrheic dermatitis, acne, androgenetic alopecia and rosacea) and their relationship to gastrointestinal dysfunction in adolescents. From August,October, 2002,2005, a questionnaire survey was carried out to obtain epidemiological data about sebaceous gland diseases. Using random cluster sampling, 13 215 Han adolescents aged 12,20 years were recruited from four countries or districts (Macau; Guangzhou, China; Malaysia; and Indonesia). The statistical software SPSS ver. 13.0 was used to analyze the data. The prevalence of seborrhea, seborrheic dermatitis, acne, androgenetic alopecia and rosacea was 28.27%, 10.17%, 51.03%, 1.65% and 0.97%, respectively. Based on multivariate logistic regression analysis, the risk factors for sebaceous gland diseases included: age; duration of local residency; halitosis; gastric reflux; abdominal bloating; constipation; sweet food; spicy food; family history of acne; late night sleeping on a daily basis; excessive axillary, body and facial hair; excessive periareolar hair; and anxiety. There was a statistically significant difference in the prevalence of gastrointestinal symptoms (halitosis; gastric reflux; abdominal bloating; constipation) between patients with and without sebaceous gland diseases (,2 = 150.743; P = 0.000). Gastrointestinal dysfunction is an important risk factor for diseases of the sebaceous glands and is correlated with their occurrence and development. [source] Estimating population size and habitat associations of two federally endangered mussels in the St. Croix River, Minnesota and Wisconsin, USA,AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2010Daniel J. Hornbach Abstract 1.North America is a globally important centre of freshwater mussel biodiversity. Accurate population estimates and descriptions of critical habitat for endangered species of mussels are needed but are hindered by their patchy distribution and the dynamic nature of their habitat. Adaptive cluster sampling (ACS) was used to estimate population size and habitat associations of two federally endangered species, Higgins eye (Lampsilis higginsii) and winged mapleleaf (Quadrula fragosa), in the St. Croix River. 2.This river holds the largest known winged mapleleaf population in the upper Mississippi River and contains Essential Habitat Areas for Higgins eye. Winged mapleleaf density ranged from 0.008,0.020 individuals m,2 (coefficient of variation=50,66%), yielding an estimate of 13 000 winged mapleleaf in this reach of the river. Higgins eye density varied from 0.008,0.015 individuals m,2 (coefficient of variation=66,167%) giving an estimate of 14 400 individuals in this area. 3.Higgins eye and winged mapleleaf were associated with areas of the overall highest mussel density and species richness, suggesting these endangered species occur in ,premier' mussel habitat. There were no differences in many microhabitat factors for sites with and without either endangered species. Select hydraulic measures (such as shear velocity and shear stress) showed significant differences in areas with and without the winged mapleleaf but not for Higgins eye. Areas that are less depositional support dense and diverse mussel assemblages that include both endangered species, with winged mapleleaf having a narrower habitat range than Higgins eye. 4.This study suggests that ACS can provide statistically robust estimates of density with 2,3 times more efficiency than simple random sampling. ACS, however, was quite time consuming. This work confirmed that of others demonstrating that larger-scale hydraulic parameters might be better predictors of prime mussel habitat than fine-scaled microhabitat factors. Using hydraulic measures may allow improved identification of potentially critical mussel habitat. Copyright © 2009 John Wiley & Sons, Ltd. [source] Coverage of recommended vaccines in children at 7,8 years of age in Flanders, BelgiumACTA PAEDIATRICA, Issue 8 2009Heidi Theeten Abstract Aim:, Evaluation of the coverage of primary diphtheria-tetanus-pertussis (DTP), poliomyelitis, hepatitis B (HBV) and measles-mumps-rubella (MMR) vaccine doses recommended before the age of 18 months in 7-year-old school children in Flanders, Belgium. Meningococcal serogroup C and DT-polio vaccines offered respectively as catch-up and booster vaccinations were also evaluated. Methods:, Parents of 792 children born in Flanders in 1997 and selected by cluster sampling were interviewed at home in 2005. Vaccination data since infancy were collected retrospectively from vaccination documents and school health records. Results:, Coverage rates were 88.0% for the first dose of MMR, and 72.0%, 84.2% and 91.4% for the recommended HBV, DTP and poliomyelitis primary vaccine doses, respectively. These rates included catch-up of missed infant MMR (4.9%) and HBV (6.4%) vaccinations. In addition, 88.3% of the target group received the DT-polio booster dose recommended at 6 years of age and 83.1% a meningococcal C vaccine dose. Preventive public health services as well as private physicians were involved to a varying extent. A lower socioeconomic status of the family was associated with a higher risk of nonvaccination. Conclusion:, Vaccinators in Flanders reach children relatively well during infancy and at school age, but catch-up of missed infant vaccine doses, especially MMR, should be optimized. [source] Varicella seroprevalence in Turkish population in CyprusACTA PAEDIATRICA, Issue 6 2007Zafer Kurugol Abstract Aim: This study was conducted to determine the age-specific seroprevalence of varicella zoster virus (VZV) infection in Turkish population in Cyprus. Methods: A total of 600 unvaccinated individuals aged 1,30 years were selected for the study with cluster sampling. Information on socio-demographic characteristics was gathered for each participant and, anti-VZV antibodies were assayed by using enzyme immune assay. Results: Of the 578 assayed samples, 486 (84.1%) were seropositive. Varicella seroprevalence increased sharply with age from 25% for the 2,3 year olds to 55, 78 and 85% for 4,5, 6,7 and 8,9 year olds, respectively. More than 90% of individuals >16 years of age were seropositive. Varicella seroprevalence was higher in large families with five and more members (91.2%) than in small families with four or fewer members (80.2%). Conclusion: The majority of varicella-zoster virus infections occur during preschool period and at the first years of schooling. Therefore, routine varicella vaccination of children would be logical in Northern Cyprus, as is currently recommended by the European Working Group on Varicella. [source] Assessing the effectiveness of a school-based oral health promotion programme in Yichang City, ChinaCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 5 2009Bao-Jun Tai Abstract,,, Objectives:, To assess the outcome of oral health promotion in schoolchildren over a 3-year period in Yichang City, Hubei, China. Methods:, In a cluster randomized controlled trial, the concept of the World Health Organization Health Promoting Schools Project was applied to primary schoolchildren. Seven intervention schools and eight control schools were randomly selected from one district by stratified cluster sampling. The study was conducted as a 3-year follow-up study. After 3 years, 661 children remained in the intervention group and 697 children in the control group. Data on dental caries, plaque accumulation, and sulcus bleeding were collected by clinical examination, while behavioural data were gathered by self-administered questionnaires. Results:, The 3-year net mean DMFS increment score was 0.22 in the intervention schools and 0.35 in the control schools (P < 0.013). A statistically significant difference in mean plaque (P < 0.013) and sulcus bleeding (P < 0.005) increment scores after 3 years was found between the two groups. Statistically significant higher scores were observed in restorations received and sealants placed, and a lower score in untreated dental caries, in children from the intervention group than the control group after 3 years (P < 0.01). In addition, more children in the intervention schools adopted regular oral health behavioural practices such as brushing their teeth at least twice a day, visiting the dentist within the past calendar year, and using fluoride toothpaste. Conclusion:, The study suggests that the school-based oral health promotion was an effective way to reduce new caries incidence, improve oral hygiene and establish positive oral health behavioural practices in the targeted schoolchildren. [source] Oral and general health behaviours among Chinese urban adolescentsCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 1 2008Poul Erik Petersen Abstract,,, Objectives:, The objectives of this study were to measure the association of general and oral health-related behaviours with living conditions and to explore the interrelationships between general and oral health-related behaviours in Chinese urban adolescents. Methods:, A cross-sectional survey of 2662 adolescents was conducted in eight Chinese provincial capitals. The response rate was 92%. The study population was selected through multistage cluster sampling and comprised three age groups: 11, 13 and 15 years. Data on oral and general health, lifestyles as well as living conditions were collected by means of self-administered structured questionnaires. Several additive indices were constructed from answers to the questions on specific behaviour, and participants were categorized according to scores on each component of health-related behaviour for statistical analyses by frequency distributions, regression analyses and factor analyses. Results:, Oral health-related behaviours among adolescents were associated with socioeconomic status of parents, school performance and peer relationships. The odds of a dental visit was 0.63 in adolescents of poorly educated parents and the corresponding figure for regular oral hygiene practices was 0.62. Odds of tobacco use was 3 for adolescents with poor performance in school while odds of consuming sugary foods/drinks was 1.3. Adolescents with high levels of preventive oral health practices also demonstrated general health-promoting behaviours. In factor analysis of general and oral health-related behaviours, three factors were isolated: (a) risk behaviours (loadings 0.48,0.66), (b) health-promoting behaviours (loadings 0.60,0.64) and (c) help-seeking behaviours (loadings 0.56,0.67). Conclusion:, The findings support a multidimensional model of health behaviour. Several approaches and multiple methods should be applied in oral health education in order to modify behaviours that affect oral health. [source] | |||||||||||||