Click on the following links. Please note these will open in a new window.

Video Links

• Scales of Measurement 
  This YouTube video uses an example to illustrate what variables are and the four scales of measurement (nominal, ordinal, interval, ratio) 
• Reliability 
  Describes the concept of reliability and the various types of reliability
• Reliability and Validity 
  This YouTube video describes reliability and validity. An example is used to illustrate whether a study is of “good quality.”

Audio Links

• The Hawthorne Effect 
  BBC Radio audio link examining the origins of the psychological effect known as participant reactivity, more commonly known as the Hawthorne effect, based on the factory productivity experiments conducted in the 1920s.
• Scientific Findings Often Fail to be Replicated Researchers Say 
  This NRP audio clip discusses the massive effort to test the validity of 100 psychology experiments. It was found that 50 percent of the studies fail to replicate, which is based on a new study published in the journal "Science."

Web Resources

• Validity 
  York University website delineating the types of validity in psychological tests as well as the appropriate tests of determining validity
• What is the Difference Between Categorical, Ordinal, and Interval Variables?   
  This website from UCLA defines these variables and explains why they are important
• Measurement: Reliability and Validity                                                                 
  This excellent PDF gives an overview of important terms such as levels of measurement, reliability and validity of measurement, and how to evaluate reliability and validity