Sarah Tipping works as a Statistician in NatCen's Research Department and specialises in sample design and weighting methods. At any one time Sarah will be involved on a number of different projects that cover a range of subject areas and require a variety of sampling or weighting techniques. She also has a strong interest in survey methodology - work in this area includes analysis of response rates and non-response bias, responsive design, mixed-mode surveys and data collection mode effects.