COM 633: Content AnalysisSampling and Units
Kimberly A. Neuendorf, Ph.D.
Cleveland State UniversityFall 2010
Defining the PopulationResearcher fiat!? Let’s discuss.“The set of units to which the researcher wishes to generalize.”Is a full sampling frame available? (e.g., population may be defined by a NEXIS search)
Population & SamplePopulation Sample
The study of its units Census Survey, experiment, or content analysis
The number of units N n
A summary number about a variable and its distribution
Parameter Statistic
The mean of a variable
µ M or X-bar
The standard deviation of a variable
σ sd
The variance of a variable
σ2 sd2
UnitsWeyls (2001); study of adult entertainment
Lombard et al. (1996); study of TV production techniques
Unit of sampling
Unit of data collection
Unit of analysis
UnitsWeyls (2001); study of adult entertainment
Lombard et al. (1996); study of TV production techniques
Unit of sampling
News story
Unit of data collection
News story
Unit of analysis
Year
UnitsWeyls (2001); study of adult entertainment
Lombard et al. (1996); study of TV production techniques
Unit of sampling
News story Time, date, channel
Unit of data collection
News story Episode, time interval, etc.
Unit of analysis
Year Episode, time interval, etc.
UnitsNational Cancer Institutes (2003); study of news about mammography
Janstova (2006); study of films by Jane Campion vs. others
Unit of sampling
Unit of data collection
Unit of analysis
UnitsNational Cancer Institutes (2003); study of news about mammography
Janstova (2006); study of films by Jane Campion vs. others
Unit of sampling
News story
Unit of data collection
Story, attribution
Unit of analysis
News story
UnitsNational Cancer Institutes (2003); study of news about mammography
Janstova (2006); study of films by Jane Campion vs. others
Unit of sampling
News story Film
Unit of data collection
Story, attribution
Film, character, 5-min. interval
Unit of analysis
News story Film, character, 5-min. interval
UnitizingUnit—one decision rule might be to select the “smallest identifiable unit for which one can reliably code for the desired variables, thus providing maximal variance for these measures across the entire unit of sampling” (p. 72)Coder unitizing vs. a priori unitizing
Unitizing reliability is necessary when coders unitize
ArchivesUnprecedented access to “archives” online!Comprehensive vs. SelectiveElectronic/online vs. nonFree vs. costly
Medium ManagementArchiving messagesSearching for messagesPreparation of messages for coding/handling during codingAutomated content analysis
SamplingRandom or Probability Sampling
Simple random sampling (SRS)Systematic sampling---------------------------------Cluster samplingStratified samplingMultistage sampling
SamplingNon-probability (nonrandom) Sampling
Convenience samplingPurposive or judgment samplingQuota sampling
Top Related