Introduction to Communications Research

Simple brook hotshot in symbiotic and whizz leechlike variable. . Testable the ability to test the family relationship among variables moldiness be clear. 4. Useful should provide freshly 3 criteria for monotheistic causal relationships 1 . Variables be correlated I. E. Describes statistical relationship between 2 variables 2. The cause takes enthrone before the proceeding (post hoc ergo decorous hoc) 3. The relationship between variables is non-spurious Monotheistic accounting is probabilistic in nature and is norm each(prenominal)y incomplete. Exceptions do not disprove a demonstrated monotheistic causal relationships. causal relationships open fire exist even if they do not apply to the majority of cases.Longitudinal Studies cross-sectional Studies Observations taken at single block in time. Ex proposalation occurs by examining differences crosswise the units of analysis (hopefully representative of population). Less expensive, yet harder to establish cause and ef fect. Observations ar taken more than once. Explanation occurs by examining differences crosswise time. More expensive, still easier to provide gumption of cause and effect. Trend Studies Examines stirs in a population crossways time. Investigator samples indiscriminately from a population over time, with contrasting individuals constituting each sample. Hard to understand wherefore change occurred as participants differ.age bracket Studies A causa of longitudinal research where an investigator haphazard samples from a but cause and effect still hard to show as surveys change. Cohort Analysis Any topic in which some characteristic of one or more cohorts is measured at two or more times. Cohort a group of people who ar linked by some vulgar characteristic of action event. Panel Studies A longitudinal consume that examines changes in individuals across time. Panel studies provide the opportunity for more in-depth analysis. Each study collects information from he same i ndividuals. Longitudinal panel studies are expensive but informative forms of research. whizz must account for attrition as each wave of information is calm from the panel. Reduce attrition by planning and persistence.Disadvantages of Longitudinal Studies 1. By the time the study is complete, the original measures go out have induce outmoded, and the overall social context will have changed. Critics will suspicion if the findings are relevant. 2. Longitudinal researchers have to accept postponed gratification. 3. grueling to secure documentation for longitudinal studies because funding iodides often press for measures relevant for cross-sectional questions, rather than longitudinal analysis. 4. Because of their expense, it will constantly be necessary to plan for twofold uses, and this carries the danger of not plowing any question thoroughly. 5. Attrition over time is an ever-present hazard.Advantages of Longitudinal Studies 1 . They allow an veracious time cabareting of events to better address monotheistic causation. 2. They allow the study of within-individual change ? a more powerful causal analyses than cross-sectional surveys. 3. Because these are multiple data mints, they provide a better supplement on the handling of missing data Week 5 Experimental visualise 1 19th and 20th one C classical experimentation 0 consecrate of holding everything constant except the one variable under consideration. 0 non controlling all potential variables, but rather manipulating levels of selected independent variables in order to examine their influence on dependent variables. authorization experimental design controls background discrepancy so that systematic effects of treatments can be observed. 1. Control by duplicate Some sources of variation may be eliminated by matching, which limits inerrability However matching is solitary(prenominal) workable on known and evident characteristics and perfect matching is never possible 2. Control by stoch asticization Converts of all irrelevant sources of possible systematic unevenness into unsystematic variability (random error) Like life insurance, a precaution against disturbances that may or may not occur and that may or may not be serious if they do occur 3. Control by statistical adjustment Uses statistical relations to simulate matching and append preciseness.Week 6 Experimental Design 2 Design Total experimental plan or structure of experimental research. Pre-test The sign observation of videodisk among subjects (prior to V). Post-test The measurement of DVD among subjects (after introduction of V). Laboratory Experiments vs. Field Experiments ecologic validity Hawthorne Effect where subjects alter their mien because they know they are being studied. As such, field experiments are often non-reactive. only if often results in lack of control, as intervening variables might affect the precision of the experiment. Pre-experiments designs follow basic experimental locomot e but fail to include a control group or random assignment. One-Shot Case Study One-Group Pre-Test-Post-Test Design