Snowball Sampling Completion

The snowball sampling, as a network research, presents numerous advantages in registering "hidden populations" such as: drug consumers, people with deviant sexual behavior, people with rare diseases which are unapproved by society, illegal immigrants, people working in the black market, but also presents a major disadvantage "“ the absence of objective, quantitative criteria in taking a decision to conclude the investigation. There is also a certain ambiguity on the number of interviewed persons, which cannot be established previously; thus, it depends on the researcher to stop the investigation when he considers the information gathered is satisfactory or sufficient relative to the objective of the investigation.

The purpose of this material is to adapt and develop the sequential method (Wald's test) for the case of hidden populations, typical situations for sociologic researches where snowball sampling is adequate.

The results obtained in this material, innovative in their development, can contribute significantly to improving sociological research methods in a special area "“ field sociologic investigation developed in closed groups.