Source:http://linkedlifedata.com/resource/umls/id/C0150105
MCM: A sample derived by selecting sampling units (e.g., individual patients) such that each unit has an independent and fixed (generally equal) chance of selection. Whether or not a given unit is selected is determined by chance, for example, by a table of randomly ordered numbers.,NCI: A method of selecting a sample from a population in such a way that every sample that could be selected has an equal chance of being selected.