The selection of the last interviewees in face-to-face opinion polls: an analysis of the joint use of the route method and the quota method

Abstract

All texts about sampling present the available methods for sample selection and the characteristics that the universe which is the object of study must possess, in order for the most suitable method to be selected. All of them point to the need to have prior knowledge of the universe before carrying out any sampling. This implies that there has to be some source that provides detailed knowledge of theobject of study domain. This requirement poses some difficulties when the samples are selected from the population in general. These difficulties are due both to the limited access to documents reporting the characteristics of the population living in a specific area, and to the inaccuracies that these documents contain. This is why the samples drawn from the
population in general use various methods of sampling jointly. In this paper, an evaluation of the quota sampling applied to the 2004 Barometers of the Sociological Research Centre is carried out.