To clarify the necessity of applying appropriate statistical methods to calculate sampling error from data of cluster sample survey, we take a two-stage cluster sample survey developed from a population aged 15 and over as example. We use statistical methods based on the assumption of simple random samples and methods considering complex sample design to analyze our data, respectively. Through comparison, we hope to show the potential effects of using improper statistical methods to estimate sampling error on parameter estimation and hypothesis testing. Using standard error algorithms based on the assumption of simple random samples,the standard errors calculated often underestimate sampling error and the hypothesis testing even gets wrong conclusion. When the statistical methods and statistics package for complex survey data are already available, it is necessary for us to use appropriate methods to analyze and report the sampling errors of data from cluster sample survey.
Cluster Analysis ; Data Interpretation, Statistical ; Epidemiologic Studies ; Sampling Studies

OBJECTIVETo estimate the number of death from malignant tumor and to assess the completeness of cancer registry data using the capture-recapture method.

METHODSData about death form malignant tumor were collected during the period of 2004 and 2005 from cancer registry, civil administration and police registries in Linzhou. Cases in every source were matched on the address, name, sex, ID card, date of death, cause of death. A 3-source log-liner poisson model was used to estimate the real number of death from malignant tumor during the period of 2004 and 2005 in Linzhou.

RESULTSThe real number of death from malignant tumor that estimated by capture-recapture method was 3140 (95% CI: 3124 - 3161) during 2004-2005 year in Linzhou. Underreported number by source linkage was 71. Log-liner model demonstrated positive dependence between the 3 sources, implying that 2-source model would underestimate missing cases. Using the mortality number estimated by the capture-recapture as the denominator, under-reporting rate of cancer registry was 6.6%.

CONCLUSIONIt is feasible to estimate the real number of death from malignant tumor and to correct data bias by applying the capture-recapture method.

China ; epidemiology ; Humans ; Neoplasms ; mortality ; Registries ; Sampling Studies

OBJECTIVETo analyze the difference and correlation of food intakes assessed by Food Weighted Record, 24 Hours Recall and Food Frequency Questionnaire (FFQ) methods.

SUBJECTSThe data of 2002 China National Nutrition and Health Survey were used. All 23,198 subjects (male 11,107, female 12,091) finished all three dietary survey methods. Food Weighted Record method weighted all food items consumed at home by all family members in last 3 days; 24 Hours Recall recorded all food items the subjects consumed at and out home in last 3 days; FFQ recorded the main 33 categories food items that the subjects consumed at and out home in last year.

RESULTSCompared to Food Weighted Record method, food intakes assessed by 24 hours recall were similar, and the relative differences were less than 10% of most food items. The proportion of over-report and under-report (+/- 25%) by 24 Hours Recall were less than 40%. The correlation coefficients of food intakes between Food Weighted Record and 24 Hours Recall methods ranged from 0.58 to 0.88. The results from Food Weighted Record and FFQ were similar among the high frequently consumed food items. The relative differences of the food intakes investigated between Food Weighted Record and FFQ were less than 15% and the proportion of over-report and under-report (+/- 25%) by FFQ were more than 50%. The correlation coefficients of food intakes between Food Weighted Record and FFQ ranged from 0.08 to 0.76.

CONCLUSIONFood intakes might be assessed accurately by the Food Weighted Record revised 24 Hours Recall method, and FFQ method be also used to assess the food intakes, especially for the frequently consumed food items, as to studying the relationship between food consumption and health.

Data Collection ; Diet Surveys ; Eating ; Female ; Humans ; Male ; Sampling Studies

No abstract available.
Statistics as Topic ; Models, Statistical ; Data Interpretation, Statistical ; Sampling Studies ; Biometry

OBJECTIVETo study the application of decision tree in the research of anemia among rural children.

METHODSIn the Enterprise Miner module of software SAS 8.2, 3000 observations were sampled from database and the decision tree model was built. The model using decision tree of CART bases on Gini impurity index.

RESULTSThe misclassification rate of decision tree model was, training set 21.2%, validation set 21.9%. The Root ASE of decision tree model was, training set 0.399, validation set 0.404. The area under the ROC curve was larger than the reference line. The diagnostic chart showed that the corresponding percentage was higher than the other. The decision tree model selected 9 important factors and ranked them by their power, among which mother of anemia (1.00) was the most important factor. Others were children's age (0.75), time of ablactation (0.53), mother's age (0.32), the time of egg supplementation (0.26), category of the project county (0.26), the time of milk supplementation (0.16), number of people in the family (0.13), the education status of the mother (0.12). Decision tree produced simple and easy rules that might be used to classify and predict in the same research.

CONCLUSIONDecision tree could screen out the important factors of anemia and identify the cutting-points for factors. With the wide application of decision tree, it would exhibit important application values in the research of the rural children health care.

Anemia ; prevention & control ; Child, Preschool ; Decision Trees ; Evaluation Studies as Topic ; Humans ; Rural Population ; Sampling Studies

OBJECTIVETo investigate level and its influential factors of occupational stressors and strains in workers of a steel plant and explore the feasibility of occupational stress and mental health as indicators of effect evaluation of health promotion at workplace.

METHODS1039 workers were investigated by using cross-sectional method. The questionnaires included job stressors, skill discretion, job control latitude, mental health and sleep disorders.

RESULTS54.5% of respondents reported "job doesn't allow mistakes" as stressor, while 47.6% of respondents reported "too job responsibility" as stressor. The scores of job stressors were significantly higher than female workers (P<0.01). Workers with high education level scored more skill discretion, job control latitude and lower mental health than ones with low educational level (P<0.05 or P<0.01). Elder workers had more skill discretion and job control latitude scores than younger. There were significant differences in scores of skill discretion among different length of service groups (P<0.05). There were also significant differences in scores of skill discretion among different job title groups (P<0.01). Occupational stressors were correlated significantly positively with sleep disorder (r=0.37, P<0.01), but job control latitude negatively to mental health (r=-0.19, P<0.01).

CONCLUSIONThe workers in the steel plant report occupational stressors, which is related to poor self-reported health symptoms. The occupational stressors and mental health should be considered as one of effect evaluation indicators of health promotion at workplace.

Adult ; Burnout, Professional ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; Sampling Studies ; Steel ; Surveys and Questionnaires

OBJECTIVETo study the relations between different feeding patterns and the body weight retention of the perinatal women living in rural areas of China.

METHODSA cluster sampling method was used to investigate 409 women, who are currently living in rural areas of Tianjin, at pregnant and perinatal status. While, their body weights and heights before pregnancy, antepartum and postpartum were measured, respectively. Body weight retention was the difference of the measured data after postpartum minus pre-pregnant weight. Variance analysis was used for statistic comparison.

RESULTSThe rate of exclusive breastfeeding was 70.9% (290/409) within four months. The net body weight retention of women (5.8 kg) using the exclusive breastfeeding was lower than that of the women (7.0 kg) using artificial feeding within 4 - 6 months, but there was no significantly statistic difference (F = 1.45, P = 0.236). However, there was the opposite result within 7 - 9 months, the data showed that the body weight retention in the women using the exclusive breastfeeding was 4.9 kg, which was significantly higher than that the women (2.9 kg) with artificial feeding (F = 3.17, P = 0.043). The food consumption of the women (901 g) using exclusive breastfeeding was the highest, followed by those (877 g) using mixed feeding and the women (750 g) using artificial feeding.

CONCLUSIONThe body weight retention after postpartum should be related to infant feeding patterns. After postpartum, the weight loss of women using the exclusive breastfeeding is relatively low. While, for the women using the exclusive breastfeeding, the net weight retention during pregnancy and after postpartum were lower than those with artificial feeding. Therefore, it is necessary to enhance health education and guidance on promoting exclusive breast-feeding as well as increasing awareness on pre-pregnant health.

Body Weight ; Breast Feeding ; Feeding Behavior ; Female ; Health Status ; Humans ; Infant ; Rural Population ; Sampling Studies

The purpose of this study was to compare the difference of two survey methods for health services research. Data were collected by means of two types of household survey conducted from March 11 to September 19, 1985. A probability sample of 30,613 persons was taken from 180 Enumerated Districts designated by the Economic Planning Board. The sample was divided into two groups systematically. One group was surveyed by the self-administered questionnaire and the other group was interviewed. Response rates were 81.4% and 90.6% respectively. The data were analyzed by the ratio of the results of the self-administered survey to those of the interview survey. No difference was observed in sex, age, residence, or occupation between the two groups. However the respondents' characteristics were statistically different between the two groups. The major findings of this study are as follows : 1. The morbidity rate was 142.5 per 1,000 persons during the two week period by the self-administered questionnaire survey and 74.3 per 1,000 persons with the interview survey method. The ratio of the morbidity rate by the self-administered questionnaire to that by the interview was 1.92, and the difference between the two rates were due to the personal characteristics. 2. The out-patient utilization rate was 10.2 visits per person per year by the self-administered questionnaire survey and 5.4 by the interview survey, and the ratio was 1.89; the admission rate was 3.2 times per 100 persons per year by the self-administered questionnaire survey and 1.9 times by the interview survey, and the ratio was 1.68. Differences due to the sociodemographic characteristics were greater in the out-patient utilization rates than in the admission rates. 3. Percentages of effective medical care demand were 90.2% in the self-administered survey and 92.3% in the interview survey; the ratio was 0.98 which was less than that of the morbidity rate and medical care utilization. But, differences of effective medical care demand occurred in persons with no occupation, and aged or low educated respondents. 4. Respiratory illness had the highest frequency in the two survey methods. But there was a slight difference between the two survey methods in morbidity composition. 5. It was concluded that data collected by the interview survey were inclined to be underestimated and this problem can be corrected by a modified self-administered survey.
Surveys and Questionnaires* ; Family Characteristics ; Health Services Research* ; Health Services* ; Humans ; Occupations ; Outpatients ; Surveys and Questionnaires* ; Sampling Studies

A Nationwide health care utilization survey was conducted from March 11 to September 19, 1985 to assess the level of illness and the magnitude of medical care utilization. A probability sample of 15,427 persons was taken from 180 Enumerated Districts designated by the Economic Planning Board. Of those 4,500 housewives were proxy respondents. A interview was conducted with pre-tested questionnaire schedule which was recorded by well trained interviewers. Age and sex compositions of the study population were similar to those of general population structure in 1985. The major findings of this survey are as follows: 1) A total of 64.5% of the study population lived in city area and 35.5% lived in county area. 2) While no difference was observed in interview rate between city and county area, it showed statistically significant difference in the medical security program coverage rate between the two areas(44.7% and 37.1%, respectively). 3) Morbidity rate was 79 per 1,000 persons during the two week periods. There was difference in age and sex adjusted morbidity rates between city and county area. Furthermore morbidity rates by the status of the program were significantly difference between the two areas. 4) Average ambulatory care utilization rate was 7.2 visits per person per year and average admission rate was 1.8 per 100 persons per year. There was significant difference in average ambulatory care utilization rate by the program. but no significant difference in medical utilization rate between city and county area. 5) The major symptoms of the perceived illness was the respiratory system(44.1%). 6) A total of 50.4% of the perceived illness among the covered group by the program were treated at the hospital and clinics, but those who are not covered used primarily drug stores(61.3%).
Ambulatory Care ; Appointments and Schedules ; Surveys and Questionnaires ; Delivery of Health Care* ; Humans ; Korea* ; Proxy ; Surveys and Questionnaires ; Sampling Studies

OBJECTIVETo survey the prevalence of dental caries and the needs for dental treatment in Anhui province.

METHODSThe survey of prevalence of dental caries in group aged 12 and 15 years in Anhui province was conducted using the non-proportional, stratified, cluster sampling method.

RESULTSDMFT in 12-year and 15-year group was 0.58 and 0.95 respectively, and permanent tooth caries prevalence rate was 30.78% and 39.78% respectively, lower than that of same age of other 11 provinces in mainland China (P < 0.01). The constituent ratio of DMFT was 90.51% (D), 2.48% (M), 7.01% (F) in 12-year group and 86.78% (D), 4.30% (M), 8.92% (F) in 15-year group.

CONCLUSIONSWhen we controlled dental caries in 19.98% 12-years crowd and 22.8% 15-years crowd of Anhui province, we will had controlled the occurrence of 80% caries too in group aged 12 and 15 years.

Adolescent ; Child ; China ; epidemiology ; Dental Caries ; epidemiology ; prevention & control ; Female ; Humans ; Male ; Prevalence ; Sampling Studies