Listwise Deletion Method Research Articles

Comparing Several Missing Data Estimation Methods in Linear Regression;Real Data Example and A Simulation Study

Analysis on incomplete could lead to biased estimation when using standard statistical procedure since it ignores the missing observations. The disadvantage of ignoring missing data is that the researcher might not have enough data to conduct an analysis. The main objective of the study is to compare the performance between listwise deletion (LD), mean substitution (MS) and multiple imputation (MI) method in estimating parameters. The performance will be measured through bias, standard error and 95% confidence interval of interested estimates for handling missing data with 10% missing observations. A complete empirical data set was used and assumed as population data. Ten percent of total observations in the population ere set as missing arbitrarily by generating random numbers from a uniform distribution, . Then, bias of parameter estimates and confidence interval of parameter estimates are calculated to compare the three methods. A Monte Carlo simulation was carried out to know the properties of missing data and investigated using simulated random numbers. Simulation of 1000 sampled data with 20, 50, and 100 observations and each sample is set to have 10% missing observations. Standard statistical analyses are run for each missing data and get the average of parameter estimates to calculate the bias and standard error of parameter estimates for every missing data method. The analysis was conducted by using SAS version 9.2. It was found that the MI method provided the smallest bias and standard error of parameter estimates and a narrower confidence interval compared to the LD and MS methods Meanwhile, the LD method gives a smaller bias of parameter estimates and standard error for small sample size of missing data. And, MS method is strongly recommended not to use for handling missing data because it will result in large bias and standard error of parameter estimates.

Adoption of E-Wallets in Indonesia: Integrating Mindfulness into the Technology Acceptance Model

This study investigates the main determinants of e-wallet use intention and proposes an e-wallet adoption model that includes mindfulness as a significant factor. The respondents in this study are e-wallet users between the ages of 17 and 40 who live in Bengkulu City. To collect data samples from respondents, the convenience sampling technique was used. This study's online survey questionnaires were distributed via social media platforms such as WhatsApp and Instagram. After using the listwise deletion method on SEM-AMOS with Mahalanobis Distance, 257 usable questionnaires were available for analysis. For data analysis, Confirmatory Factor Analysis (CFA), assessment of normality, and regression weights were used in this study. According to the findings, (1) mindfulness has a positive and significant effect on perceived usefulness, (2) mindfulness has a positive and significant effect on perceived ease of use, (3) perceived usefulness has a positive and significant effect on the intention to use, (4) perceived ease of use has no significant effect on the intention to use, and (5) intention to use has a positive and significant effect on actual use. This study adds to the body of knowledge by extending the concept of TAM through the incorporation of mindfulness variables into a structural model. It is suggested that providers expand their merchant partners in order to provide more benefits to customers, and that they improve more features and benefits for people who use their apps. Furthermore, this study discovered some limitations, which include a) limited geographical areas for data collection, giving opportunity for future research to expand more and will be much better if can compare respondent characteristics between cultures; b) four dimensions of mindfulness must be validated again when applied to other contexts; and c) future research can look at post-purchase phenomenon to catch e-wallet adoption even better.

초등학교 입학 이후 아동의 개인 요인과 학교 환경 요인이 학교 적응에 미치는 종단연구

Objectives The purpose of this study was to analyze longitudinally the effect of individual factors (gender, self-esteem, academic performance, and maternal parenting behavior) and school environmental factors (teacher-child relations) on the school adjustment of children after entering elementary school.
 Methods This study used the longitudinal data from 8th to 11th cycles (2016-2018) surveyed from 1st grade to 4th grade of elementary school by the Childcare Policy Research Institute. The listwise deletion method was used to solve the missing values in the longitudinal data, and the final 252 students (male=127, female=125) data were used. Through multi-level growth analysis, this study analyzed the changes of elementary school students individual and school environmental factors on school adjustment after elementary school enrollment.
 Results First, it was discovered that school adjustment of children in the first through fourth grades of elementary school was insufficient but increased over time. Second, while controlling for the gender of elementary school students, only academic performance had a statistically significant positive effect on the trajectory of changes in school adjustment of children in the first to fourth grades of elementary school. Third, while controlling for the gender of elementary school students, it was discovered that the teacher-child relationship had a statistically significant positive effect on the change in school adjustment of children in the first to fourth grades of elementary school. Fourth, among the individual variables, only gender and teacher-child relationship as school environmental factors had a statistically significant positive effect on the change in school adjustment of children in the first to fourth grades of elementary school.
 Conclusions Through this results, the implications for successful school adjustment of children were discussed.

IMPACT ON PROJECT SUCCESS THROUGH HUMAN RESOURCE MANAGEMENT AND KNOWLEDGE MANAGEMENT: MEDIATION MODEL FROM COMPETENCY

The impact of development perspective of human resource management and lesson learned system of knowledge management on project success with the mediation of project management competency retention is examined by collecting the data from the regular employees of telecommunication sector (PTCL, Ufone, Warid, Zong and Mobilink), GEPCO and Sui Northern Gas Pipeline limited of Gujranwala District of Punjab, Pakistan. For this purpose 380 questionnaires were distributed out of which 321 questionnaire were returned and the study gains an actual response rate of 84.4%. Some questionnaires were excluded because of missing values by using list-wise deletion method which includes particular statistical analysis and after that 310 complete questionnaires were selected for further proceeding. The relationship of Development Perspective of Human Resource Management, Lesson Learned System of Knowledge Management and Project Success with mediation of Project Management Competency Retention is examined by using the statistical techniques such as “Pearson’s Correlation”, “Descriptive Statistics” and “Factor Analysis”. The results confirmed that development perspective of human resource management and lesson learned system of knowledge management has insignificant positive relationship with project management competency retention and project success. There is no mediation of project management competency retention has been proved between development perspective of human resource management, lesson learned system of knowledge management and project success. A significant positive relationship has been proved between project management competency retention and project success. Finally the results suggested that it is crucial for the organizations to retain competency to achieve project success.

OPINION LEADERSHIP MEMODERASI eWOM INTENTION (STUDI PADA BOMBARU BAR DAN RESTO BENGKULU, INDONESIA)

Abstract. The purpose of this study was to examine the influence of Self-Relevant Value, Quality Value and Perceived Informational Utility on Electronic Word-Of-Mouth Intention moderated by Opinion Leadership in Bombaru Bars and Restaurant Bengkulu, Indonesia consumers. The respondents of this study were 17-45 years old. Respondent data were collected by the survey questionnaire provided. After adopting the listwise deletion method through Mahalanobis Distance on SEM-AMOS, 133 questionnaires that could be used were available for analysis. Data analysis used Confirmatory Factor Analysis (CFA), assessment of normality, and regression weights. The Result indicate that (1) Self-relevant Value has a positif effect on eWOM Intention; (2) Quality Value has a positif effect on eWOM Intention; (3) Perceived Informational Utility has a postif effect on eWOM Intention; (4) Opinion Leadership moderates the influence of Self-relevant Value on eWOM Intention; (5) Opinion Leadership moderates the influence of Quality Value on eWOM Intention; (6) Opinion Leadership moderates the influence of Perceived Informational Utility on eWOM Intention.Keyword: eWOM Intention, Opinion Leadership, Perceived Informational Utility, Quality Value, and Self-relevant Value.

The Effectiveness of Educational Mobile Messages for Assisting in the Prevention of Early Childhood Caries: Protocol for a Randomized Controlled Trial.

BackgroundIn 2017, approximately 3.7 billion downloads of health apps were made on mobile phones and tablets. In this sense, a massive number of people could benefit by electronic mobile–based health interventions, making information available even with the lack of material and human resources. Hence, the use of electronic apps for dental education might be extremely useful for the prevention of early childhood caries (ECC).ObjectiveThis study aims to evaluate the effectiveness of messages sent via mobile phones as an adjuvant method for the prevention of ECC.MethodsA single-blinded, randomized, and parallel-group clinical trial will be conducted with dyads of parents or caregivers and children aged between 36 and 60 months, recruited from kindergartens and schools of Bauru, São Paulo. The determination of sample size resulted in a total of 104 dyads of parents and children, considering a power of 80%, a significance level of 5%, and an attrition of 30%. This sample will be randomly assigned to test and control groups, being divided in 52 dyads per group according to the health literacy levels of parents and the age, gender, and oral health status of children. Every 2 weeks, only participants in the test group will receive messages via WhatsApp containing preventive and education-related ECC information. The dyads will visit the dentist every 3 months during a year for the assessment of primary outcomes (sugar consumption and the International Caries Detection and Assessment System, visible plaque, and community periodontal indices) and to receive dental care measures. Secondary outcomes (electronic health literacy and general perceived self-efficacy) will be determined only at baseline and after 12-month follow-up. The quality of randomization will be evaluated throughout the study, comparing the test and control groups systematically by Student t tests for continuous variables and chi-square tests for categorical variables. Listwise deletion method will be applied in cases of dropouts, if the missing values satisfy the criteria of missing completely at random; otherwise, multiple imputation data strategy will be conducted. The Kolmogorov-Smirnov and Levene tests will be used to determine the normality and homogeneity of data, respectively, which will indicate further statistical analyses for elucidating significant differences between groups (P<.05). A Student t test or Mann-Whitney U test will be employed for parametric or nonparametric analyses, respectively.ResultsThe project was funded in 2018, and enrollment was completed in August 2019. Allocation is currently under way and the first results are expected to be submitted for publication in 2020.ConclusionsThe results will contribute to understanding the importance of educational mobile messages toward the adoption of healthy behaviors for the prevention of ECC in a given population.Trial RegistrationBrazilian Registry of Clinical Trials Universal Trial Number U1111-1216-1393; http://www.ensaiosclinicos.gov.br/rg/RBR-2b6r7q/International Registered Report Identifier (IRRID)PRR1-10.2196/13656

The Impact of Development Perspective of HRM and Lesson Learned System of Knowledge Management on Project Success

The impact of the development perspective of human resource management and lesson learned system of knowledge management on project success. The mediating role competency retention is examined by collecting the data from the regular employees of the telecommunication sector. A total of 380 questionnaires distributed, out of which 321 questionnaires were returned, and the study gained an actual response rate of 84.4%. Some surveys were excluded because of missing values using the list-wise deletion method, which includes a statistical analysis, and after that, 310 complete questionnaires were selected for further proceedings. The results confirmed that the development perspective of human resource management and lesson learned system of knowledge management has an insignificant positive relationship with project management competency retention and project success. There is no mediation of project management competency retention that has been proved between the development perspective of human resource management, and lesson learned system of knowledge management, and project success. A significant positive relationship has been shown between project management competency retention and project success. Finally, the results suggested that the organizations must retain competency to achieve project success.

Efficient estimation in a regression model with missing responses

This article examines methods to efficiently estimate the mean response in a linear model with an unknown error distribution under the assumption that the responses are missing at random. We show how the asymptotic variance is affected by the estimator of the regression parameter, and by the imputation method. To estimate the regression parameter, the ordinary least squares is efficient only if the error distribution happens to be normal. If the errors are not normal, then we propose a one step improvement estimator or a maximum empirical likelihood estimator to efficiently estimate the parameter.To investigate the imputation’s impact on the estimation of the mean response, we compare the listwise deletion method and the propensity score method (which do not use imputation at all), and two imputation methods. We demonstrate that listwise deletion and the propensity score method are inefficient. Partial imputation, where only the missing responses are imputed, is compared to full imputation, where both missing and non-missing responses are imputed. Our results reveal that, in general, full imputation is better than partial imputation. However, when the regression parameter is estimated very poorly, the partial imputation will outperform full imputation. The efficient estimator for the mean response is the full imputation estimator that utilizes an efficient estimator of the parameter.

College students’ apparel shopping orientation and brand/product preferences

PurposeThe purpose of this study is to provide detailed information about the shopping behaviors and brand/product preferences of college students. To accomplish this purpose the following objectives were proposed: to identify college student segments’ underlying clothing shopping orientations; to profile these consumers by demographics and brand/product preferences; and to use apparel expenditures to further characterize the market segments.Design/methodology/approachA survey of college students at a major university was conducted. After adopting the listwise deletion method, 185 useable questionnaires were available for analysis. For data analysis, descriptive statistics, K‐means cluster analysis, Chi‐square, ANOVA, and Dunnett T3 tests were employed. Results showed that three segments were identified (i.e. apathetic price‐forward shoppers, hedonic fashion‐forward shoppers, involved price‐forward shoppers), and the three hypotheses were supported.FindingsThe paper shows that the three segments can be characterized by distinct profiles of demographics and brand/product preferences. Marketing and merchandising strategies for retailers are provided.Originality/valueFew studies have examined college students’ specific brand/product preferences even though information about these consumer preferences can be directly and practically utilized by apparel retailers for their merchandise planning. There is also a lack of studies that examined college students' clothing behavior based on their major. With the increasing importance of brand as a marketing tool, this information is important to academic researchers and retailers.

Principled missing data methods for researchers

The impact of missing data on quantitative research can be serious, leading to biased estimates of parameters, loss of information, decreased statistical power, increased standard errors, and weakened generalizability of findings. In this paper, we discussed and demonstrated three principled missing data methods: multiple imputation, full information maximum likelihood, and expectation-maximization algorithm, applied to a real-world data set. Results were contrasted with those obtained from the complete data set and from the listwise deletion method. The relative merits of each method are noted, along with common features they share. The paper concludes with an emphasis on the importance of statistical assumptions, and recommendations for researchers. Quality of research will be enhanced if (a) researchers explicitly acknowledge missing data problems and the conditions under which they occurred, (b) principled methods are employed to handle missing data, and (c) the appropriate treatment of missing data is incorporated into review standards of manuscripts submitted for publication.

Missing Observations on a Variable: When Do the Listwise Deletion and Indicator Approaches Work?

Econometric analyses widely use the listwise deletion approach - which is also called the complete case method - and the indicator approach for models with censored regressors and regressors with missing observations. Nevertheless, the existing literature provides few studies which examine the statistical properties of these methods and they suggest the listwise deletion method generates smaller bias than the indicator method. Using the Monte Carlo simulations this study shows sometimes the listwise deletion estimates have larger bias than the indicator estimates when missingness on a regressor is correlated with unobserved error terms and the value of the regressor. These conditions indicate that greater care is warranted in interpreting the estimates under each approach than the existing literature and the applications which generally employ these methods.

Nonlinear Relationship Between Length of Residence and Depression in a Community-Based Sample of Vietnamese Americans

Length of residence has been viewed as an indicator of acculturation among immigrants and refugees in their host society. This study aims to test an inverted U relationship between length of residence and depression in a community-based sample of Vietnamese Americans. Data were collected from a community-based survey of adult Vietnamese Americans living in an East Coast metropolitan area consisting of 349 respondents aged 18 and older. However, due to missing data, the actual sample in our regression analysis using listwise deletion method is 311. Among the participants, 52.1% are female (n = 182), and 47.9% are male (n = 167). The age of the respondents ranges from 18 to 73 years with the average age being 38.76 (SD = 13.76). The average number of years that the participants lived within the United States was 7.01 years (SD = 5.22). Findings from a polynomial regression analysis support the hypothesis that depression levels tend to be high during the first decade of initial resettlement. However, after approximately 12.5 years, depression levels decrease. As revealed by the data and community experts, immigrants/ refugees tend to suffer from higher levels of psychological problems during their first decade of resettlement. It takes more than a decade for a non-English-speaking immigrant or refugee to adjust psychologically into his/her host society.