What is Validity and Reliability?
Our text is pretty weak in this area so I have supplemented with some informative web sites. • Validity: There are two general types Validity related to the participants and the research design. This is usually divided into internal validity and external validity. Validity related to the data collection instrument (such as a questionnaire or interview). • Reliability: This usually has to do with HOW the data were collected (data is plural by the way and so if you want to be a really cool research nerd, you’ll remember that fact!) • Remember the MAX-MIN-CON Principle! maximizing the experimental variance (the independent variable) minimize the error variance (the reasons there are differences in the dependent variable) controlling extraneous variance A fatal flaw: This is some horrendous Validity or Reliability error that invalidates the study results. They are somewhat subjective. For example, I consider contamination a major internal validity fatal flaw, a response rate of 20% a major
