Search

Minimum discriminant information adjustment (MDIA), an approach to weighting samples to conform to known population information, provides a generalization of raking and poststratification. In the case of simple random sampling with replacement with uniform sampling weights, large-sample properties are available for MDIA estimates of population means and related functions of such means. This research report provides large-sample properties of MDIA estimates under complex sampling designs, such as stratified and two-stage sampling. Cases are considered for both sampling with replacement and sampling without replacement. MDIA is one case of calibration weighting, and this report includes results showing that sample calibration weights can exist only if MDIA weights exist, and MDIA weights can exist in situations where other calibration weights do not. Similarly, results in the report show that calibration weighting does properly generalize MDIA for populations. To illustrate results and explore the use of large-sample approximations in samples of moderate size, an application from Florida middle schools is examined for several sampling procedures to evaluate MDIA estimates for the prevalence of literacy coaches in those schools.

ObjectiveHealth behavior was conducive to control the coronavirus disease (COVID-19) epidemic. This study aimed to determine the differences in health behaviors and related factors among rural and urban residents in China.MethodsFrom February 14 to 22, 2020, during the peak of the COVID-19 epidemic in China, a total of 2449 participants (1783 (72.81%) urban residents and 666 (27.19%) rural residents) were recruited by snowball sampling on WeChat and QQ social platforms, both owned by Tencent. Data were collected through the Web-questionnaire guided by an information-motivation-behavioral skills model. The multiple-group structural equation model was applied to analyze the factors.ResultsRural residents had lower health behavior scores than urban residents, even after adjusting demographic characteristics (33.86 vs 34.29, P = 0.042; total score was 40). Motivational, behavioral skills, and stress had direct positive and negative influences on health behaviors of urban and rural residents. Information and positive perception of interventions had direct effects on health behaviors in rural residents, but not in urban residents. All the factors were mediated by behavioral skills in rural and urban residents.ConclusionsThis study suggests that the government should pay attention to substantial rural and urban disparities and implement different COVID-19 prevention and intervention policies for health behaviors targeting rural and urban residents.

Many assessments of writing proficiency that aid in making high-stakes decisions consist of several essay tasks evaluated by a combination of human holistic scores and computer-generated scores for essay features such as the rate of grammatical errors per word. Under typical conditions, a summary writing score is provided by a linear combination of the holistic scores and the feature scores. The best linear predictor (BLP) is used to approximate the true composite writing score by a linear combination of holistic scores and scores of essay features. However, because the relationship between computer-generated feature score and human scores may depend on subgroup membership and the same scoring rules must normally be applied to all test takers, Yao, Haberman, and Zhang proposed a modified methodology of the penalized best linear predictor (PBLP) by incorporating a quadratic penalty function into the conventional BLP method. This research report contains full accounts of the BLP results as well as supplementary PBLP results to Yao et al. for three assessments of writing that aid in making high-stakes decisions: the "TOEFL iBT"® Writing test, the "GRE"® General Analytical Writing subject test, and the "Praxis"® Core Academic Skills for Educators: Writing assessment. Results obtained indicate the added value in using machine features for prediction of composite true scores of essay writings and effectiveness of the penalty function in suppressing the lack of population invariance.

ObjectiveTo ascertain the causes of a food poisoning incident and provide references for the prevention of similar incidents in the future.MethodsCase investigation was conducted through field epidemiological investigation methods， and suspicious meals and foods were searched by the analytical epidemiological method. A food hygiene investigation was conducted in the establishment involved and samples of suspicious food， processing steps， and cases were collected for laboratory testing.ResultsA total of 91 individuals meeting the case definition were identified， resulting in an attack rate of 14.97% （91/608）. The main clinical manifestations included abdominal pain （97.80%）， diarrhea （84.62%）， nausea （62.64%）， vomiting （72.53%）， fever （12.09%）， and increased white blood cells （90.11%）. The peak incidence occurred from 16：00 to 18：00 on June 15. The epidemic curve showed a point-source exposure pattern， with an incubation period of 1 h minimum and 10 h maximum， and an average of 5 h. Analytical epidemiological studies indicated that lunch on June 15 was the suspicious meal （χ2=38.78， P