Even if we are sampling census tracts we may not be able to measure everyone who is in the census tract.
Some people argue that sampling errors are so small compared with all the other errors and biases that enter into a survey that not being able to estimate is no great disadvantage.
Sample Size and Population Size Why is a sample of 1, considered to be adequate for most survey research—even when the population is much larger than that?
Population Parameter vs. Common methods of conducting a probability sample of the household population in the United States are Area Probability Sampling, Random Digit Dial telephone sampling, and more recently, Address-Based Sampling. They can also be costly but are generally less so than in-person interviews.
This study aims to understand the change and level of change in one of the two variables in study, if the other variable changes.
Finally, online sampling offers great ease of implementation and tremendous cost-benefit over the other approaches. I got compensated nicely, I don't mind saying, for coming up with this scheme.
Conducting a national-level survey of the general population with a standard screening approach to identify Chinese Americans would result in a very low yield, resulting in a very expensive survey.
Then methods such as simple random sampling or systematic sampling can be applied within each stratum. A non intrusive method of collecting feedback is important to achieve a higher number of responses.
Sullivan noted in the surveillance reports, CDC does not do weighting or adjustment; they minimize biases by having a consistent process but report essentially raw numbers.