APPENDIX B
The Samples

For each of the six coalfields selected for study it was decided to aim at interviewing the following number of people.

The Sampling Method

(a) The districts visite d

Within each coalfield the various districts were grouped according to the proportion of miners among the insured workers. The correct proportions of parents and boys were then allocated to certain administrative districts chosen to represent these groups. A list of the towns and districts in which interviews were made is given below:-

(b) The selection of parents

The names and addresses of the parents were obtained from the local Food Office in each administrative district. Cards were selected at equal intervals from the files of blue Food Reference Leaves, which apply to young people aged 6-18. After rejecting cards relating to all girls and to boys under 13 years, the remaining boys were classified as coming from mining or non-mining families according to the father’s occupation as given in the 1939 National Registration Schedules. Sufficient addresses were obtained in this way to make it unnecessary to interview more than one parent in each household visited.

(c) The selection of boys

The Schoolboys were selected from class lists and were interviewed at school. The working boys were interviewed in their places of work. Ministry of Labour figures giving the number of boys engaged in the different industries in each district were used to allocate them to the various industries was excluded.

The Resulting Samples

By the end of the survey the following number of interviews had been completed: