The 1975 Integrated Census of the Population and Its Economic Activities (ICPEA) is the first quinquennial census to gather information on the economic activities of the population. It involved a two‑phase operation: the first phase dealt with the collection of socio‑demographic data of all persons; the second, covered data gathering of the economic characteristics of persons 10 years old and over who were engaged in activities like farming/gardening, livestock and poultry raising, fishing, manufacturing, and other household operated activities for the period from January 1 to December 31, 1975. The objective of Phase II is to measure the productivity of the household and the income and employment generated by household operated activities. Definitions of terms and concepts can be found in the explanatory text of the ICPEA publication.
For Phase II, the sampling frame used was the listing of all household heads in about 40,000 barangays all over the country. A 10% sample in all urban barangays and a 5% sample households in all rural barangays were selected for personal interviews. A systematic selection with a random start of households (sample) within each barangay were made. A total of 454,844 sample households were interviewed. The ICPEA report contains the estimation procedures employed. Responses were pre-coded.