Research Designs

Case Study

• Case study: brings together wide range of information on single individual or group, including interviews, observations, or test scores
• Best used to study unique type of individuals
• May be influences by researcher biases
• Findings may not generalize

Ethnography

• Ethnography: participant observation of a culture or distinct social group
• Mix of observations, self-reports, interpretation by investigator
• Results can be biased by the researcher
• Findings are limited to the individuals and settings studied

Correlation Design

• Correlational research: researchers gather information and look at the relationship between 2 more naturally occurring characteristics, behaviors, or ideas (ie variables)
• Correlation is not causation
• The strength and direction of the relationship is important
• Correlation coefficient: a number from -1 to +1 that indicates the strength and direction of the relationship between variables
• Direction: the sign +/- of the correlation coefficient indicates the direction of the relationship
• Strength: the closer the number is to +1 or -1, the more strongly related the variables
• Positive correlation: the variables move in the same direction
• Negative correlation: the variables move in opposite directions

Experimental Design

• Experimental design: investigates cause and effect relationships
• Manipulate variables to determine change, as well as cause and effect
• Control as many aspects of the situation as possible (internal validity), in order to generalize the results (external validity)
• Independent variable: the variable the investigator expects to cause changes in another variable
  • What is being manipulated
• Dependent variable: the variable being measured
  • The outcome

Longitudinal Design

• Longitudinal design: gathers data from one group of individuals at several points of time
• Gives us the clearest picture of how the variables we’re interested in change as a function of age
• One of the biggest threats is attrition

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