Compara mètodes

	Mostreig doble	Mostreig sistemàtic
Camp	Mostreig	Metodologia d'enquestes
Família	Process / pipeline	Process / pipeline
Any d'origen	1938	Mid-20th century (Cochran 1953; Kish 1965)
Autor original	Jerzy Neyman	William G. Cochran; formalized in survey sampling theory
Tipus	Multi-phase sampling design	Probability sampling design
Font seminal	Neyman, J. (1938). Contribution to the theory of sampling human populations. Journal of the American Statistical Association, 33(201), 101–116.	Cochran, W. G. (1977). Sampling Techniques (3rd ed.). John Wiley & Sons. ISBN: 978-0471162407
Àlies	Two-Phase Sampling	interval sampling, systematic random sampling, equal-interval sampling, fixed-interval sampling
Relacionats	4	5
Resum	Double Sampling (also called two-phase or multistage sampling) is a survey design in which a large preliminary sample is collected using inexpensive methods or partial information, then a smaller subsample is drawn from it and measured in detail. Pioneered by Jerzy Neyman in 1938, it is particularly useful when a cheap surrogate measurement is available but true measurement is expensive.	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.