The Coloured people of the Cape Peninsula have evolved over three hundred years as a demarcated ethnic group with recognizable physical features and characteristic cultural and social conditions. As such they constitute a very satisfactory population for epidemiological and transcultural studies, and when the need arose to plan for improved psychiatric services, a large-scale field survey of the prevalence and types of mental illness was set afoot. Since socio-economic circumstances appear to be very relevant to the amount and type of mental illness in a community, special estimations of these were also made. Random sampling of the entire population of Coloured persons over 20 years of age in the magisterial area of the Cape Peninsula was done and 500 of a total population of 200,365 people were interviewed about their mental and physical health, as well as a variety of economic and social circumstances, by a team of three psychiatrists and 14 specially trained social workers. In addition, interviews were held with reliable persons who knew each respondent, such as ministers of religion, social workers, housing managers, nurses, doctors, friends, relations, and employers. Hospital records were consulted as necessary, and the information was evaluated for each respondent by a team of three psychiatrists. The data were coded and finally exposed to an extensive computer and statistical analysis.
Quantifying supply chain food loss in China with primary data: A large-scale, field-survey based analysis for staple food, vegetables, and fruits
