Undercoverage. Oftentimes, an accurate and complete list of the population is unavailable. In such cases, one or more groups will be omitted from the sampling process because they are not listed as part of the population. This type of bias is called undercoverage.

a. Explain why a sample survey of households will generally suffer from undercoverage.

b. Provide another example where bias due to undercoverage is likely to occur.