A History of the Ministry of Information, 1939-46
1. SAMPLE
1.1 The sample was originally designed to meet the wishes of the Department of Scientific and Industrial Research for analysis by geographical regions, by income in two groups and by family size in two groups. It was based upon the assumption that the minimum number of interviews likely to be significant in any of these groups in any region was 100. The distribution of interviews was decided in relation to the Ministry of Food returns of population figures, and within each of the Ministry's main regions the principal urban centres were represented, roughly in proportion to the population, with a minimum of 20 in any one town. It was thought that in this way each of the geographical regions would be adequately represented.
The method of choosing the sample within each town was as follows: a list of the streets in which it was believed that families in the chosen income groups lived was prepared in consultation with the Local Authority - usually the Rating Officer - and the quota for the town selected at random from these streets.
After the field work had been completed, however, it was decided that the regional analyses should be made on the basis of a Degree-Day chart * , which was thought to give a more precise indication of climatic differences than regions chosen merely as northern, southern or western. Since the Degree-day regions agree only roughly with geographical regions this has resulted in a somewhat unequal distribution of interviews between the four Degree-day regions finally chosen. Where local differences rather than temperature differences were considered to be important, however, geographical regions also have been used.
The rural sample has also been affected by this change. It was originally decided to use it only for the two geographical regions, Scotland and the North, and Southern England. By the Degree-day system it is now scattered through each Degree-day region roughly in proportion to the rural population of the country as a whole.
The sample with these revisions has three principal divisions, urban, rural, and urban flats. The latter is a special sample of flats taken in London, Liverpool, Leeds and Glasgow in order to be certain that the number of flats represented in the sample, as a whole, would be sufficient to allow of comparisons in expenditure to be made with houses.
1.2 SAMPLE. REGIONALLY AND NATIONALLY
Degree-Day Regions
| (i) 5,000 - 5,500 Degree Days | 152 |
| (ii) 4,500 - 5,000 Degree Days | 1,405 |
| (iii) 4,000 - 4,500 Degree Days | 1,856 |
| (iv) Under 4,000 Degree Days | 1,847 |
| Total | 5,260 |
Geographical Regions
1.3 URBAN AND RURAL
The rural calls were made round selected market towns in Scotland and the North of England and across southern England and South West. The number of rural and urban interviews is as follows:-
a list of towns for all these interviews, with an indication where rural calls have been made, is given in Appendix
[1] Degree-Day: a unit, based upon temperature difference and time, used in specifying the nominal heating load in winter. For any one day there exists as many degree-days as there are degrees Fahrenheit difference in temperature between the average outside air temperature, taken over a 24 hour period, and a temperature of 65 o F.
The annual, total of Degree-Days is the sum of the number of Degree-days for every day in the year.
1.4 URBAN FLATS
These have been taken in four towns in the following numbers:-
In the analyses this sample has been added to the flats already found in the sample taken at random. The total of flats is, therefore, 1064.
1.5 INCOME GROUPS
All the interviews have been taken from two income groups only, chosen by the Department of Scientific and Industrial Research, namely below £160 per annum family income and £160 - 300 per annum family income. It must be noted that the enquiry is thus concerned with the lower paid section of the working class. The respective numbers are:-
1.6 FAMILY SIZE
The Department required division of the sample into family groups of 1-3 and 4-7. The numbers are:-
1.7 CONCLUSION
All the tables are based upon these figures, but in several cases where house-wives have for one reason or another not answered a question the total figures for these questions will be considerably lower than the total given above. Where expenditure is concerned the total figure used is only two-thirds of the above owing to difficulties in obtaining complete details of expenditure on gas and electricity.