Correlation Research

• Correlational research


  A type of non-experimental research where researchers do not measure or control anything, they simply take two (or more) variables and calculate whether a statistical relationship exists between them
• Correlational research


  • The data used may come from existing archives such as government statistics or data from past research or it might be gathered through self-report measures or observations of behaviour
  • Strictly speaking a correlation isn't a research method as such, but a way psychologists can measure the strength between two or more co-variables (things that are measured)
  • When there are two variables in the research design, one is called the predictor variable and the other is called the outcome variable
• Correlational research example


  • A psychologist may test whether there is a correlation between playing violent video games (predictor variable) and aggressive behaviour (outcome variable)

  
• Scatter plot


  A way to illustrate correlational research where a point is plotted for each individual at the intersection of their scores for the two variables
• Positive correlation


  When one variable increases, the other also increases, and if one variable decreases, the other will also decrease
• Negative correlation


  When one variable increases, the other decreases
• Correlation coefficient (r)


  • A statistical technique to calculate the strength of a relationship between two variables, ranging from -1 to +1
  • The closer the number gets to 1 in either direction, the stronger the relationship between the variables is
• Curvilinear relationship


  An association between variables that does not consistently follow an increasing or decreasing pattern but rather changes direction after a certain point
• Strengths of correlational research


  • Useful when experimental research is not possible due to practical or ethical reasons
  • Can enable us to make predictions about behaviour
  • Uses real world data that is typically more applicable to everyday life compared to data gathered in a lab setting
• Limitations of correlational research


  • The validity of the research is dependent on the measures used to collect the data
  • Correlations might show a relationship exists but not why it exists
  • Correlation does not imply causation
• Spurious correlation


  A mathematical relationship in which two or more events or variables are correlated but not causally related, due to either coincidence or the presence of a certain third, unseen factor
• Third variable problem


  An observed correlation between two variables may be due to the common correlation between each of the variables and a third variable rather than any underlying relationship (in a causal sense) of the two variables with each other
• Directionality problem


  When there is a correlation between two variables and there is uncertainty about which variable is influencing which