PSC 202 1st Edition Lecture 7 Outline of Last Lecture I. The literature reviewII. Literature Search StrategiesOutline of Current Lecture I. Experiments II. Quasi ExperimentsCurrent LectureI. Experiments - conditions for causality1. the variables covary (change together)2. change in x precedes the change in y3. alternative causes are eliminated - key attributes1. control of independent variable2. measurement of dependent variable3. exclusion of alternative causes- research design considerations1. internal validity: isolation of the effects of independent variable on dependent variable2. external validity: the ability to generalize beyond the experiment to other settings - controlled comparison: accomplished by examining the relationship between an independent and a dependent variable, while holding constant other variables suggested by rival explanations and hypotheses- compositional difference: any characteristic that varies across categories of an independent variable- spurious relationship: the control variable defines a large compositional difference across values of the independent variableThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- additive relationship: the control variable is a cause of the dependent variable but defines a small compositional difference across values of the independent variable- interaction relationship: the relationship between the independent variable and the dependent variable depends on the value of the control variableII. Quasi Experiments- Research methods that seek to mimic conditions of a controlled experiment- Often exploit a naturally occurring process - Basic steps1. randomly assign2. manipulate something 3. set a baseline4. measure the dependent variable5. analyze differences in the dependent variable between the treatment and thecontrol groups- why quasi?1. the researcher does not control the selection process2. the researcher may not control the independent