Сравнение на методи

	Пропорционално систематично подбиране	Клъстерно извадково изследване
Област	Методология на проучванията	Методология на проучванията
Семейство	Process / pipeline	Process / pipeline
Година на възникване	Mid-20th century (formalized ~1950s–1970s)	Early-to-mid 20th century; canonical treatment 1953/1977
Създател	Codified in classical survey sampling theory; see Cochran (1977)	Formalized by William G. Cochran; roots in early 20th-century U.S. Census Bureau survey practice
Тип	Probability sampling design	Probability sampling design
Основополагащ източник	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). Wiley. ISBN: 978-0471162407	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). Wiley. ISBN: 978-0471162407
Други названия	proportional 1-in-k sampling, equal-probability systematic sampling, proportionate systematic selection, PPS systematic sampling	cluster random sampling, area sampling, one-stage cluster sampling
Свързани	6	5
Резюме	Proportional systematic sampling combines systematic (every k-th element) selection with proportional allocation across subgroups, ensuring that each stratum contributes sample units in proportion to its share of the total population. The result is an equal-probability design that is administratively simple, spreads the sample evenly across an ordered frame, and eliminates the need for post-hoc weighting when strata are sampled at a uniform rate.	Cluster sampling is a probability sampling technique in which the population is divided into naturally occurring groups (clusters), a random sample of clusters is selected, and all — or a random subset of — members within each selected cluster are studied. It is especially practical when a complete population list is unavailable or when units are geographically dispersed, making individual random selection prohibitively expensive. One-stage cluster sampling surveys every member of selected clusters; two-stage designs add a second random draw within clusters.