Most of the surveys are sample surveys. These are preferred in statistics because of number of reasons. A sample can provide reasonably reliable and accurate information at a lower cost and short time. As the size of the sample is small as compared to the population, the time and cost involved on sample study are much less than the complete Counts. For complete count huge funds are required. There is always the problem of finance.
As a sample is smaller than the population, more detailed information can be collected by conducting intensive enquires. It is suitable when universe comprises units of homogeneous nature whereas survey method is used when universe comprises units of heterogenity. Therefore, we can say that sample provide better results than survey method.