Vigitel--Aracaju, Sergipe, 2008: the effects of post-stratification adjustments in correcting biases due to the small amount of households with a landline telephone.

INTRODUCTION: The Telephone Survey has several attractions, such as low operational costs and speed the process, when compared to the Household Survey. However, the exclusion of house holds without a landline phone canpose a serious question of the valid it yof the estimates. OBJECTIVE: Evaluating the use of post stratification adjustments to correct the potential biasdue to low coverage of landline phonein the results published in the Vigitel system. METHODS: We compared the prevalence obtained by the Household Survey and the Vigitel, in Aracaju, Sergipe, where 49% of households had a telephone, calculating the differences measured between the surveys thatused the square root mean square error as a measure of accuracy of the estimate. RESULTS: The Household Survey showed ten variables associated with landline phone. From this set of variables, post stratification weights corrected the potential bias of the consumption of beans in five or more days per week, vegetables intake regularly and recommended self-assessment of health as bad and morbidity of diabetes,while the weights partially eliminated the bias of the prevalence of asthma, possession of health insurance coverage and prevention of breast cancer in women aged 50 to 59 years. CONCLUSIONS: In order to reduce the potential bias in the results published by Vigitel system, in areas with low telephone coverage, it becomes necessary to use alternative weighting procedures and selection strategy of external variables for construction of post-stratification weights.

Vigitel - Aracaju, Sergipe, 2008: the effects of post-stratification adjustments in correcting biases due to the small amount of households with a landline telephone / Vigitel - Aracaju, Sergipe, 2008: efeitos da pós-estratificação na correção de vícios decorrentes da baixa cobertura de domicílios com telefone fixo

INTRODUCTION: The Telephone Survey has several attractions, such as low operational costs and speed the process, when compared to the Household Survey. However, the exclusion of house holds without a landline phone canpose a serious question of the valid it yof the estimates. OBJECTIVE: Evaluating the use of post stratification adjustments to correct the potential biasdue to low coverage of landline phonein the results published in the Vigitel system. METHODS: We compared the prevalence obtained by the Household Survey and the Vigitel, in Aracaju, Sergipe, where 49% of households had a telephone, calculating the differences measured between the surveys thatused the square root mean square error as a measure of accuracy of the estimate. RESULTS: The Household Survey showed ten variables associated with landline phone. From this set of variables, post stratification weights corrected the potential bias of the consumption of beans in five or more days per week, vegetables intake regularly and recommended self-assessment of health as bad and morbidity of diabetes,while the weights partially eliminated the bias of the prevalence of asthma, possession of health insurance coverage and prevention of breast cancer in women aged 50 to 59 years. CONCLUSIONS: In order to reduce the potential bias in the results published by Vigitel system, in areas with low telephone coverage, it becomes necessary to use alternative weighting procedures and selection strategy of external variables for construction of post-stratification weights. .

INTRODUÇÃO: O Inquérito por Telefone, quando comparado ao Inquérito Domiciliar, apresenta vários atrativos, em especial baixo custo operacional e rapidez do processo de divulgação de resultados. No entanto, a exclusão de domicílios sem telefone fixo pode apresentar problemas na validade externa das estimativas. OBJETIVO: Avaliar os efeitos do uso de pós-estratificação para corrigir vícios decorrentes da baixa cobertura de domicílios com telefone nos resultados divulgados no sistema Vigitel. MÉTODOS: Comparar resultados levantados no Inquérito Domiciliar com Vigitel no município de Aracaju, Sergipe, cuja cobertura era de 49% de telefonia fixa. O vício do Vigitel foi expresso pela diferença entre as prevalências do Vigitel e do Inquérito Domiciliar, sendo calculada a raiz quadrada do erro quadrático médio como medida de acurácia da estimativa. RESULTADOS: O Inquérito Domiciliar apontou dez variáveis associadas à posse de linha telefônica residencial (LTR). Desse conjunto de variáveis, os pesos de pós-estratificação corrigiram os vícios potencias do consumo de feijão em cinco ou mais dias por semana, consumo de folhas, legumes e verduras (FLV) regularmente e recomendado, autoavaliação de saúde considerada ruim e morbidade referida de diabetes,enquanto os pesos eliminaram parcialmente o vício da prevalência de asma, posse de plano de saúde e a cobertura de prevenção de câncer de mama em mulheres de 50 a 59 anos. CONCLUSÕES: Tendo em vista a redução dos vícios potencias nos resultados divulgados pelo sistema Vigitel, em regiões de baixa cobertura de telefone fixo, torna-se necessário o uso de procedimentos de ponderação alternativo e a estratégia de seleção ...