Wiji Arulampalam and Alison L Booth, "Union Status of Young Men in Britain: A Decade of Change", Journal of Applied Econometrics, Vol. 15, No. 3, 2000, pp. 225-252. The data used in the article are from the National Child Development Study. We obtained the data from Peter Shepherd, City University, London and Peter Elias, Institute for Employment Research, University of Warwick, at the time the data were being cleaned prior to public access. The data are now available from the U.K. Data Archive at the University of Essex. Permission to use this data should be obtained from the U.K. Data Archive. SPSS software was used to create the relevant variables for the analyses presented in this paper. The relevant programs are provided and these have a file extension .sps and are stored in the zipped file called spsfiles. The data were then fed into Limdep for the econometric analyses. These files have an extension .lim and are stored in the zipped file called limfiles. The files were zipped using winzip. Please address any questions to: Wiji Arulampalam, Department of Economics, University of Warwick, Coventry, CV4 7AL,UK. wiji.arulampalam@warwick.ac.uk June, 1999.