The Wellcome Trust Longitudinal Population Study (LPS, which includes studies like ALSPAC) Strategy states that research methods are needed to i) underpin efficient linkage of multiple datasets, ii) quantify potential biases resulting from linkage and how this impacts on results, and iii) to handle linkage error in data analyses. Our study aims to maximise the value of LPS by providing improved methods for linkage and analysis, building on previous work in these areas.