Towards a new view of evaluation: quality media research in today's world

Robert M. Groves
University of Michigan and University of Maryland, United States

Ed Cohen
Domestic Radio Research, Arbitron Inc., United States

Ricardo Gomez-Insausti
Research, BBM, Canada

INTRODUCTION

One unique value of sample surveys as a tool to document human thought and behavior is their ability to describe large populations without bias and within measurable levels of uncertainty. While the mathematical probability theories required for this inference are centuries old (Pearson, 1903), and their application to samples of humans about 70 years old (Neyman, 1934), recently we have been reminded that this power of surveys is dependent on full measurement of a probability sample. That is, the original theories assume that nonresponse is absent. However, in the past few decades developed countries have seen an increase in the rate of sample persons not being measured (de Leeuw and de Heer, 2002). Hence, it is important to understand the potential impact of nonresponse on the ability of surveys to describe large populations.