Census and Sample Survey
Census and sample surveys essentially relate to the statistical collection of data across various areas and sectors pertaining to the particular subject matter or inquiry. These data collection exercises are undertaken on a cross-section of a targeted population. The information that is derived from the study of a population can be subsequently used for various purposes. Let us discuss the census and sampling.
The Census Method is also known as a Complete Enumeration Survey Method. In this method each and every item in the universe is selected for the data collection. The selected data might constitute a particular place, a group of people, or any specific locality that is the complete set of items and which are of interest in any particular situation. This method is most commonly used by the government in connection with the national population, housing census, agriculture census, etc. where vast knowledge about these fields is required.
Census Method
The process used in the census method includes the statistical compilation of all units or members of the target population under the survey. In this case, population relates to the entire set of observations connected to a particular study. For instance, if students of a university have to give feedback on teaching faculty, the former will be held as the population of that study.
Sample Method
Sample method chooses the different sample entities from the targeted population. This method involves a statistical analysis of an already determined number of observations that is derived from a larger set of populations. Sample methodology can be used of different kinds; these can be – simple random sampling or systematic sampling, cluster sampling or stratified sampling, etc. among others.
Limitations of Census Method
The expenditure incurred during the census is much higher because of the sheer size of the population. Also, data is collected from each unit of a sample population, which requires additional costing.
Owing to the huge volume of data that is collated, a greater number of the workforce (as well as man-hours) is required for completion.
Costly Method: Census method is a very costly method of data collection.
Time Consuming: Census method consumes more time and labor to complete data collecting tasks.
Unsuitability: Census method is not applicable or suitable if the universe is large. This method is suitable only for a small universe.
Chance Of Errors: There is a comparatively higher chance of statistical errors in this method.
Advantages of Sample Method
In the sampling method, the number of units utilized is significantly less. It helps to arrive at results much quicker.
Sample method incurs substantially lower cost than the census method as these tests are done over a limited sample.
It has greater scope than the census method as it acts as a substitute in such cases where the latter becomes impracticable. For instance, if a manufacturer wants to test its range of toasters and other kitchen appliances, it will apply a sample method and not a census method.
The nature of the sample method is such that it can be employed to check the results from the census method. Also, due to the small size of its sample, the method is useful for cross-checking the reliability of its own results. A small sample can be taken out of generated results, and that sample will have to be investigated.
Accuracy And Reliability: Census method confirms a higher degree of accuracy than other techniques. The Census method provides complete information because each and every item is investigated carefully. Therefore, it is a very reliable method of data collection.
Suitability: Census method is effective if the universe is small.
Intensive Study: Census method examines each unit completely and gathers important data for intensive study.
Indispensable: Census method is most reliable in certain cases where other methods cannot provide reliable and accurate results.
Heterogeneous Units: This method is also applicable to examine heterogeneous units.
Sample Survey
A sample survey is a type of method that is used for collecting data from or about the members of a population so that inferences about the entire population can be obtained from a subset, or sample, of the population members. A sample survey provides an estimate of the average length of stays for surgical and nonsurgical discharges would be calculated and compared. A well-defined sample survey will support inference from the sample that is scientifically valid about the population.
Advantages of Sample Survey
Low cost of sampling: The cost will be quite high if the data of the sample survey is collected for the entire population. The cost will be lower if data collected for sample surveys is for a sample of population which is a big advantage.
Less time-consuming in sampling: A sample survey takes less time. A sample survey consumes less time than a census technique.
Scope of sampling is high: A sample survey makes it possible to arrive at generalizations by studying the variables within a relatively small proportion of the population.
Accuracy of data is high: Drawing a sample and computing the desired descriptive statistics, A sample survey makes it possible to determine the stability of the obtained sample value. A sample survey permits a high degree of accuracy due to a limited area of operations.
Organization of convenience: Organizational problems are very few in sample surveys. The sample is of small size, vast facilities are not required in it. The sample survey is therefore economical in respect of resources. The study of samples in sample surveys involves less space and equipment.
Limitations of Sample Survey
Chances of bias: A sample survey involves biased selection and thereby leads to drawing erroneous conclusions. Bias selection arises when the method of selection of sample employed is faulty. Comparatively small samples properly selected may be much more reliable than large samples poorly selected.
Difficulties in selecting a truly representative sample: Difficulties in selecting a truly representative sample produce the most reliable and accurate results only when they are representative of the whole group. Selection of a sample is difficult when the phenomena under study are of a complex nature. Selecting good samples for a survey is difficult.
Inadequate knowledge of the subject: The sampling method requires adequate subject knowledge in sampling technique. Sampling involves statistical analysis and calculation of error for surveying. When the researcher lacks specialized knowledge in sampling, they commit serious mistakes in sample surveying.
The changeability of units: If the units of the population are not homogeneous, the sampling technique will be unscientific. In this sampling method, though the number of cases is small, surveying is not always easy to stick to the selected cases. The units of the sample may be dispersed widely.
Difference between Census And Sample Survey
FAQs on Census vs. Sample Survey: A Comparison
1. What is the difference between a census survey and a sample survey?
A census survey involves collecting data from every member of a population, while a sample survey gathers information from only a subset of the population. This distinction is important in statistics and data collection.
- Census survey: Data is collected from all individuals in the target group.
- Sample survey: Only a representative portion or sample of the population is surveyed.
- Census surveys offer more accurate results but are time-consuming and expensive. Sample surveys are quicker and less costly but may be less accurate if the sample isn't chosen well.
2. What is a census survey?
A census survey is a method used to collect detailed information from every single member of a defined population. This approach ensures that all individuals or units are included, leaving no section unrepresented. Census surveys are commonly used by governments for population counts, such as the decennial population census. Because a census survey covers everyone, it provides highly accurate and comprehensive data for policy-making, resource allocation, and demographic analysis. However, conducting a census requires significant time, planning, and expense, which is why such surveys are usually carried out infrequently. In conclusion, a census survey is best when complete and precise data from a whole group is needed for reliable results.
3. What is meant by sample survey?
A sample survey is a technique in which information is gathered from a small, carefully selected group (sample) that represents a larger population. Instead of surveying everyone, researchers collect data from just part of the group and use these findings to estimate results for the entire population. This method is frequently used in market research, opinion polls, and scientific studies where it is not practical to survey everyone. Sample surveys are more economical and less time-consuming than censuses, but care must be taken to choose a representative sample to avoid bias. In summary, a sample survey helps make predictions about a large group by studying a manageable segment.
4. What is the difference between a survey and a census?
The terms "survey" and "census" both refer to data collection methods, but they differ in scale and scope. A census is a specific type of survey that aims to cover every member of a population, leaving no one uncounted. In contrast, the term "survey" is broader and can include any process of collecting information, either from the entire population or just a part (sample).
- Census: Collects data from all individuals in the population.
- Survey: May collect data from the whole population (census) or only from a sample (sample survey).
5. What are the advantages of a census survey?
A census survey offers complete information about every member of a population, making it highly accurate for statistical analysis and decision-making. Because it does not rely on sampling, potential biases are minimized, and the results are considered reliable for planning and resource distribution.
- Comprehensive data: Every individual or unit is counted, increasing accuracy.
- Allows for detailed sub-group analysis (for example, by region or age).
- Reduces the risk of sampling error or selection bias.
6. In what situations is a sample survey preferred over a census?
A sample survey is usually chosen over a census when the population is very large, making it difficult or costly to reach every member. Other situations favoring sample surveys include time constraints, limited resources, or when repeated data collection is necessary.
- Cost and time efficiency: Sampling saves both resources and effort.
- When quick decisions are needed based on ongoing or changing data.
- For destructive testing, where examining every unit would ruin the items (e.g., product quality tests).
7. What are the limitations of a sample survey?
While sample surveys are efficient, they have some limitations. The biggest challenge is ensuring the sample accurately represents the population, as errors in sample selection can lead to biased results.
- Sampling bias: Poor sampling methods can misrepresent the larger group.
- Results are estimates, not exact values, so there is always some uncertainty.
- Smaller samples may miss rare features or small subgroups.
8. How is a representative sample selected for a sample survey?
Selecting a representative sample is crucial for accurate results in a sample survey. Statisticians use various sampling techniques to ensure their sample mirrors the population’s characteristics as closely as possible.
- Random sampling: Every member has an equal chance of selection, reducing bias.
- Stratified sampling: Population is divided into groups, and samples are taken from each group to reflect their proportion.
- Systematic sampling: Samples are picked at regular intervals from a sorted list.
