Compară metode

	Eșantionare ponderată proporțional	Eșantionare Sistematică
Domeniu	Metodologia anchetelor	Metodologia anchetelor
Familie	Process / pipeline	Process / pipeline
Anul apariției	Mid-20th century (formalized 1950s–1960s)	Mid-20th century (Cochran 1953; Kish 1965)
Autorul original	William G. Cochran; Leslie Kish	William G. Cochran; formalized in survey sampling theory
Tip	Probability sampling design	Probability sampling design
Sursa seminală	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407
Denumiri alternative	proportional probability weighting, proportional weight sampling, probability proportional to size sampling, PPS sampling	interval sampling, systematic random sampling, equal-interval sampling, fixed-interval sampling
Înrudite	6	5
Rezumat	Proportional weighted sampling is a probability-based survey design in which each subgroup (stratum or cluster) of the population is sampled and weighted in proportion to its true size in the population. By assigning sampling weights that mirror the actual composition of the population, the method ensures unbiased estimates without the need for post-hoc reweighting, and produces efficient estimates when variance within subgroups is relatively homogeneous.	Systematic sampling is a probability sampling technique in which every k-th element is selected from an ordered list of the population after a random starting point. With population size N and desired sample size n, the sampling interval k = N/n is computed and one unit is chosen at random from the first interval; all subsequent units are selected by adding k repeatedly. The method is operationally simple, yields a spread-out sample, and often achieves lower variance than simple random sampling when the list has no harmful periodicity.