Compară metode

	Eșantionare Stratificată Proporțională	Eșantionare Sistematică
Domeniu	Metodologia anchetelor	Metodologia anchetelor
Familie	Process / pipeline	Process / pipeline
Anul apariției	1953–1965 (formalized in survey sampling literature)	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	proportionate stratified sampling, proportional allocation stratified sampling, PSRS, proportionate stratified random sampling	interval sampling, systematic random sampling, equal-interval sampling, fixed-interval sampling
Înrudite	6	5
Rezumat	Proportional stratified sampling divides the target population into non-overlapping strata (subgroups defined by a key characteristic such as age band, region, or gender) and then draws a simple random sample from each stratum so that each stratum's share of the total sample matches its share of the total population. Because each subgroup is represented in exact proportion to its population weight, the resulting sample mirrors the population structure closely without requiring post-hoc weighting adjustments.	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.