Breaking down the question
The question asks specifically about the census method — the strategy of complete enumeration in which every unit of the population is studied rather than a sample. The command word “Discuss” calls for a reasoned account of the difficulties, not a mere list.
The examiner is testing whether you understand what distinguishes census from sampling and can therefore identify the challenges that flow from trying to cover an entire population — challenges of cost, coverage, time, quality control and non-sampling error.
At 10 marks, a good answer defines the method briefly, then organises the challenges into clear categories, showing awareness that completeness brings its own distinctive problems even as it removes sampling error.
How to approach it
Open by defining the census method as complete enumeration of every unit in a defined population, contrasting it with the sample method that studies only a representative part. This framing lets you show why certain problems are intrinsic to the census approach.
Then discuss the challenges under organised heads — resources and cost, time and periodicity, coverage and access, quality and non-sampling errors, and respondent-related problems. Our notes on techniques of data collection develop these points further.
Conclude by noting that despite these challenges the census remains indispensable for certain purposes, so the difficulties are managed rather than avoided.
Model answer
The census method involves the complete enumeration of every unit belonging to a defined population — for example, every household in a country, as in the decennial Census of India. Because no unit is left out, it eliminates sampling error and can provide authoritative figures even for small sub-groups and localities. Yet the very ambition of covering everyone generates a distinctive set of challenges.
The most obvious challenge is that of resources. A full census demands enormous financial outlay, a vast trained workforce of enumerators, extensive logistics and elaborate administrative machinery. Few organisations other than the state can mount such an exercise, and even for governments the cost is a serious constraint. Closely linked is the challenge of time: because complete enumeration is slow and expensive, it can be conducted only at long intervals, so the data risk becoming dated between rounds and cannot easily capture rapid change.
Coverage and access pose further difficulties. Reaching remote, hilly, forested or conflict-affected areas, counting migrant and homeless populations, and enumerating people who move between places all threaten completeness. Under-coverage of marginal groups, or double-counting of mobile ones, undermines the accuracy the census is supposed to guarantee. Because so many field workers are involved, maintaining uniform standards is hard, and non-sampling errors — mistakes in questioning, recording, coding and processing the huge volume of returns — can accumulate. Paradoxically, a large sample survey with well-trained staff may sometimes yield better quality data than a sprawling census.
Respondent-related challenges are also significant. People may misunderstand questions, forget or misreport facts such as age and income, conceal sensitive information about caste, religion, occupation or property, or refuse to cooperate out of suspicion or fatigue. On contentious items enumeration can even become politically charged. Finally, the sheer scale of data generated creates challenges of compilation, tabulation and timely dissemination, so that results may appear well after the reference date.
In conclusion, the census method secures completeness and precision but at the price of high cost, long periodicity, difficulties of coverage, vulnerability to non-sampling error and problems of respondent cooperation and data processing. These challenges explain why sample surveys are often preferred for routine enquiries, even though the census remains irreplaceable where exhaustive, small-area data are essential.
Examiner's perspective
The examiner expects the answer to be anchored in the distinctive logic of complete enumeration, not a generic discussion of data-collection problems. A frequent shortcoming is to confuse census challenges with sampling problems, when in fact the census eliminates sampling error and instead struggles with cost, coverage and non-sampling error.
Strong answers define the method against sampling, then group the challenges into coherent categories and illustrate them, ideally with a reference to the Census of India. A closing note that the census remains indispensable despite these difficulties conveys balanced judgement within the 10-mark limit.