Which of the following sources of data is not based on primary data collection ?

Concept. Data are classified by who generated them, not by who prints them. Primary data are produced first-hand by the investigating agency itself, which goes into the field and records observations from the original units of enquiry through enumeration, interviewing or canvassed schedules. Secondary data already exist because some other agency collected them earlier; a later body only assembles, tabulates and reproduces those figures. The decisive test is therefore whether the agency behind the source carried out its own field collection, or merely compiled numbers gathered elsewhere.

Application. Apply that test to each source named in the stem:

• Census of India — the Office of the Registrar General and Census Commissioner deploys enumerators who visit every household in the country and record particulars on a canvassed schedule. The figures come into existence through that field operation, so the source generates its own data.

• National Sample Survey — the National Sample Survey Office fields trained investigators in a sample of villages and urban blocks, who canvass detailed schedules on employment, consumption expenditure and allied subjects. Again the agency itself creates the observations.

• National Family Health Survey — the International Institute for Population Sciences, with its field agencies, interviews sampled households on fertility, nutrition and health indicators. The interview in the household is the moment the data are born.

• Statistical Abstract of India — this is a compendium published by the Central Statistics Office of the Ministry of Statistics and Programme Implementation. It gathers tables already prepared by other ministries, departments and statistical agencies and arranges them in one reference volume. The publishing body runs no field enquiry of its own; every series in it was collected by somebody else beforehand.

Cross-check. Notice the naming itself corroborates the classification. Three of the four titles name an act of collection — a census, a sample survey, a family health survey — and each carries its own field staff, sampling design and schedule. The fourth is titled an "abstract", the standard label for a summary or digest of figures drawn from other publications. A compilation of that kind is the textbook example of a secondary source.

Result. The Statistical Abstract of India is the source that is not based on primary data collection; it is a secondary compilation of statistics originally collected by other agencies.