Comparison of estimates of population-based surveys

To compare estimates obtained through household and telephone surveys for monitoring, intervention and development of health policies.

The study analyzed data from 2,526 and 1,900 individuals aged 18 and over, living in Campinas, SP, interviewed by the household survey (ISACamp) and by the telephone survey (Vigitel), respectively. Sex, age and schooling were used to characterize the studied population. Prevalence estimates and 95% confidence intervals were utilized in the analysis. The estimates of the sociodemographic characteristics of the population were compared by t-test for two independent samples and the comparison of the other estimates, according to the type of survey, was performed using Poisson regression.

No statistically significant differences were found between the estimates obtained by the two surveys analyzed for overall prevalence of: overweight/obesity, smoking status, mammography in the prior year and Pap smear at least once in life. However, for the estimates of worse perceived health status, health plan affiliation, mammography at least once in life and Pap smear in the prior year, significant differences were found, with a tendency to overestimate data from the telephone survey, except in the case of worse perceived health status.

These findings point to the need for further studies, which may contribute to a better understanding of the differences, given that telephone surveys can provide quick and essential information for monitoring modifiable risk factors for the assessment of interventions and to develop policies promoting health in Brazil.