Influência das variáveis contextuais no desempenho das equipes nos últimos 10 minutos do jogo de handebol / The influence of contextual variables on the team's performance in the last 10 minutes of the handball match

O objetivo do presente estudo foi verificar a associação dos diferentes indicadores de desempenho, registados nos últimos 10 minutos do jogo de handebol, com o desfecho da partida em função da qualidade do adversário, local e equilíbrio do jogo. A amostra foi constituída por 1551 processos ofensivos e 1549 processos defensivos registados em 150 períodos de 10 minutos, observados em 75 jogos, realizados por nove equipes da Liga Portuguesa de Handebol de Seniores Masculinos na época de 2008/2009. Para o registro dos dados foi desenvolvido um sistema de observação, composto por oito variáveis de desempenho (relação numérica, fase do jogo, substituições, ações ofensivas, ações defensivas, sanções disciplinares, resultado da posse de bola e resultado do jogo) e três variáveis contextuais (local do jogo, qualidade do adversário e equilíbrio da partida). A análise da relação entre o desempenho, o resultado da partida e as variáveis contextuais foi feita com recurso ao teste do Qui-quadrado e aos modelos log-lineares. Os resultados obtidos sugerem que os indicadores associados ao resultado final são: a eficácia do goleiro, a eficácia de finalização, as substituições defesa-ataque e o número de contra-ataques. O equilíbrio da partida relaciona-se significativamente com o número de substituições, as interrupções do ataque por faltas defensivas, a eficácia de finalização da 1ª linha e os erros ofensivos

The purpose of this study was to verify the association of different performance indicators, registered in the last ten minutes of handball game, with the match outcome according to quality of opposition, game location, and match equilibrium. The sample consisted of 1551 offensive processes and 1549 defensive processes recorded in 150 ten-minute periods from 75 matches played by nine teams from the Portuguese Handball Men League in the 2008/2009 season. The observational system included eight performance variables (numerical relationship, game phase, substitutions, offensive actions, defensive actions, personal punishments, result of ball possession and match outcome) and three contextual variables (game location, quality of opposition and match equilibrium). The relationship between performance and contextual variables has been analyzed using log-linear models and chi-square test.The results suggest that the indicators associated with the match outcome are: the goalkeeper efficacy, the shot efficacy, the defense-attack substitutions and total of fast breaks. The match equilibrium was significantly related to the number of substitutions, defensive fouls, offensive errors and the efficacy of long-distance throws

Estimation of the Frequency of Intravenous Drug Users in Hamadan City, Iran, Using the Capture-recapture Method / 한국역학회지

OBJECTIVES: The number of illicit drug users is prone to underestimation. This study aimed to use the capture-recapture method as a statistical procedure for measuring the prevalence of intravenous drug users (IDUs) by estimating the number of unknown IDUs not registered by any of the registry centers. METHODS: This study was conducted in Hamadan City, the west of Iran, in 2012. Three incomplete data sources of IDUs, with partial overlapping data, were assessed including: (a) Volunteer Counseling and Testing Centers (VCTCs); (b) Drop in Centers (DICs); and (c) Outreach Teams (ORTs). A log-linear model was applied for the analysis of three-sample capture-recapture results. Two information criteria were used for model selection including Akaike's Information Criterion and the Bayesian Information Criterion. RESULTS: Out of 1,478 IDUs registered by three centers, 48% were identified by VCTCs, 32% by DICs, and 20% by ORTs. After exclusion of duplicates, 1,369 IDUs remained. According to our findings, there were 9,964 (95% CI, 6,088 to 17,636) IDUs not identified by any of the centers. Hence, the real number of IDUs is expected to be 11,333. Based on these findings, the overall completeness of the three data sources was around 12% (95% CI, 7% to 18%). CONCLUSION: There was a considerable number of IDUs not identified by any of the centers. Although the capture-recapture method is a useful and practical approach for estimating unknown populations, due to the assumptions and limitations of the method, the results must be interpreted with caution.

An Approach to Survey Data with Nonresponse: Evaluation of KEPEC Data with BMI / 예방의학회지

OBJECTIVES: A common problem with analyzing survey data involves incomplete data with either a nonresponse or missing data. The mail questionnaire survey conducted for collecting lifestyle variables on the members of the Korean Elderly Phamacoepidemiologic Cohort(KEPEC) in 1996 contains some nonresponse or missing data. The proper statistical method was applied to evaluate the missing pattern of a specific KEPEC data, which had no missing data in the independent variable and missing data in the response variable, BMI. METHODS: The number of study subjects was 8,689 elderly people. Initially, the BMI and significant variables that influenced the BMI were categorized. After fitting the log-linear model, the probabilities of the people on each category were estimated. The EM algorithm was implemented using a log-linear model to determine the missing mechanism causing the nonresponse. RESULTS: Age, smoking status, and a preference of spicy hot food were chosen as variables that influenced the BMI. As a result of fitting the nonignorable and ignorable nonresponse log-linear model considering these variables, the difference in the deviance in these two models was 0.0034(df=1). CONCLUSION: There is a lot of risk if an inference regarding the variables and large samples is made without considering the pattern of missing data. On the basis of these results, the missing data occurring in the BMI is the ignorable nonresponse. Therefore, when analyzing the BMI in KEPEC data, the inference can be made about the data without considering the missing data.