Editing Randomization (section)

=== Randomized controlled experiment ===
[[File:Sampling experiments.jpg|thumb|Educational tools used to extract a random sample from a pool]]
In the realm of scientific research, particularly within [[Clinical study design|clinical study designs]], constraints such as limited manpower, material resources, financial backing, and time necessitate a selective approach to participant inclusion.<ref name=":3" /><ref name=":4" /> Despite the broad spectrum of potential participants who fulfill the inclusion criteria, it is impractical to incorporate every eligible individual in the target population due to these constraints. Therefore, a representative subset of [[treatment groups]] is chosen based on the specific requirements of the research.<ref name=":5" /> A [[Random sampling|randomized sampling method]] is employed to ensure the integrity and representativeness of the study. This method ensures that all qualified subjects within the target population have an equal opportunity to be selected. Such a strategy is pivotal in mirroring the overall characteristics of the target population and in mitigating the risk of selection bias.

The selected samples (or continuous non-randomly sampled samples) are grouped using randomization methods so that all research subjects in the sample have an equal chance of entering the experimental group or the control group and receiving corresponding treatment. In particular, the random grouping after the research subjects are stratified can make the known or unknown influencing factors between the groups basically consistent, thereby enhancing the comparability between the groups.<ref name=":4" />