Pew Research Center designed this study to assess the current state of online survey sampling methods – both probability-based and opt-in – and determine their accuracy on general population estimates ...

Data collection is the process of gathering and measuring information used for research. Collecting data is one of the most important steps in the research process, and is part of all disciplines ...

Women living with and without HIV, age 30-65 years, were recruited in South Africa. Self-collected vaginal samples and clinician-collected cervical samples were tested with Xpert HPV, an assay that ...