MASS MEDIA RESEARCH AND INTRODUCTION NINTH EDITION ROGER D. WIMMER JOSEPH R. DOMINIC CHAPTER 02
ELEMENTS OF RESEARCH
To understand empirical research its necessary to understand the basic knowledge of concepts, construct, variables sand measurement. Concept is an idea, abstract, observation and explanation .Concept summarizes related observations and expresses an abstract notion that has been formed by generalizing from particulars. Due to two reasons, concepts are important because they simplify the research process by combining particular characteristics and researcher use meaningful summaries to deliver this information to others. While a construct is an image or idea specifically invented for doing research and theory building purpose. Constructs are a combination of different concepts which performed as building blocks of theory.
Variables are phenomenon or events that take one or more different values. Independent variables are manipulated by the researcher, whereas dependent variables are what the researcher attempts to explain. Independent variables become cause while dependent variables are affected by independent variables. Discrete or continuous variables are mostly used in mass media research. Discrete variables have fixed values which cannot be changed for example gender and religion while continuous variables can be divided into points for example height and weight. Control variables cannot be changed unpredictably during the experiment. Intervening variables existence is inferred but it cannot be measured. It explains the association between variables. All variables are related to the observable world by operational definition. Kerlinger(2010) stated two types of operational definition which is measured definition “how to measure variables” and operational definition “how investigator manipulates a variable. Researchers frequently use scales to measure complex variables that do not easily lend them solve to the single item. Turnstone, Guttmann, Linkert and Semantic differential scales are used in mass media research. In mass media research scales are used to measure attitude toward a specific medium and program. Simply rating scales which are common in mass media research investigator frequently asked questions to the respondent to rate a list of program and items provide more points which enable the respondent to differentiate easily. To develop Turnstone scale researcher collect a large number of the statement (recommends at least 100) that relates to the concept or construct to be measured. Turnstone scale is used to measure attitude toward a given concept or construct. While Guttmann scale is based on idea requires a great deal of time and energy to develop. Mostly not used in mass media research but common in political science, sociology, public opinion research and anthropology. Linkert scale is common in mass media compile a large number of statements that relate to the specific dimension. Statements consist both positive and negative facts. Investigator consistently codes the response and analyzes the responses and select for final scale. Three general factors activity, potency and evolution are measured by the semantic differential scale. Measurement is the assignment of numerical to objects, events or properties according to certain rules. To be useful a measurement must be both reliable and valid.