As part of its electronic data collection programme, the Office for National Statistics is planning to introduce web collection in the UK Labour Force Survey. In this paper, we describe the design of the pilot, including the split sample design and the various multi-mode designs that we would like to evaluate. The set of designs we would like to consider includes a simple sequential design and a two-phase hybrid design. In the latter, the first phase involves selecting a large sample of addresses to invite them to register for the LFS on the web, and to obtain basic information about the household. In the second phase, a subsample of the full sample will be selected for a Face to Face (FtF) interview; the addresses in the sample that register for a web collection and are not selected for a FtF interview will be contacted for a web collection.
We are considering a modular structure to the LFS questionnaire, with a cross-topic module, for all addresses selected for interview, and a number of topic-specific modules, each module assigned to a subset of the addresses. We will discuss the implications this will have on the sampling design and sample size.
We also present proposals for measuring mode effects and adjusting for them in estimation for each of the multi-mode designs we consider, and discuss the potential practical problems we could encounter when undertaking the pilot, including field management.