Background Nationally-representative surveys suggest that females have a higher prevalence of HIV than males in most African countries. Unfortunately, these results are made on the basis of surveys with non-ignorable missing data. This study evaluates the impact that differential survey nonresponse rates between males and females can have on the point estimate of the HIV prevalence ratio of the...

A caesarean section (CS) is a life-saving surgical procedure when certain complications arise during pregnancy and labor. However, it is a major surgery and is associated with immediate maternal and perinatal risks and may have implications for future pregnancies as well as long-term effects still being investigated [1]. CS rates have been increasing worldwide to as high as 25 to 30 %, and are ...

Despite recent and growing interest in using Twitter to examine human behavior and attitudes, there is still significant room for growth regarding the ability to leverage Twitter data for social science research. In particular, gleaning demographic information about Twitter users-a key component of much social science research-remains a challenge. This article develops an accurate and reliable ...

Guttmacher Institute/IUSSP their responses. The researchers found that many respondents had interpreted questions differently from the intended meaning and that nonsampling error was much greater than standard sampling error. They concluded that using qualitative research techniques to supplement and complement quantitative techniques can improve data validity and reduce nonsampling error. In s...