Mediamark Research 
Fall 2001 Technical Guide

Dropped Clusters

 
When designing the sample for each year, MRI selects more clusters than are needed to obtain the desired number of interviews. MRI subsequently reduces the number of clusters in each stratum or PSU using probability sampling procedures. The remaining clusters are "held in reserve." During the course of interviewing, originally selected clusters may be "dropped" or replaced by a withheld cluster, using probability sampling procedures, for a number of reasons. Among these reasons are: households in a cluster are group quarters, selected addresses are all commercial establishments or the cluster is inaccessible because it is in a high-crime area or high security area. In compliance with reporting standards required by MRC guidelines, the number of replaced clusters in the Fall 2001 study is reported as follows:

 

Total Number of Originally Selected Clusters Replaced 

178

 

Number Replaced In The Top Ten Markets 

 

103

Number Replaced In Non-Top Ten Markets 

75

Total Number of Withheld Clusters Replaced 

54

 

Number Replaced In The Top Ten Markets 

 

46

Number Replaced In Non-Top Ten Markets 

8

 

Spanish Speaking Population

At the present time, the MRI questionnaire and product information booklet are only available in English. When the selected respondent within a household is not able to participate in an English language interview, attempts are made to make use of a translator. This translator may be either a family member, a neighbor or the interviewer. If it is not possible to find an individual to carry out this translation, no interview is conducted. As a result of this procedure, the Spanish speaking population covered by the MRI study is limited to Spanish speaking individuals who are English language capable or who live in households with at least one English language capable individual. We believe that the partial use of bi-lingual interviewers or neighbors results in an extension of this covered population to a larger portion of the non- English language capable population. However, because these individuals are not always present, we have chosen to be conservative in our coverage descriptions.

As a result, we define the Spanish Language population to be Spanish Language individuals who are English Language capable or who live in households with at least one English Language capable individual.

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