methods
longitudinal analysis
longitudinal research
longitudinal study
sampling
Sampling error consists of two components: sampling variance and sampling bias. Sometimes overall sampling error is referred to as sampling mean squared error (MSE), which can be decomposed as in the following formula: where P is the true population value, p is the measured sample estimate, and p' is the hypothetical mean value of realizations of p averaged across all possible replications of the sampling process producing p. [Source: Encyclopedia of Survey Research Methods; Sampling Error]
sampling error