SAGE Research Methods Video

SAGE Research Methods videos feature a variety of academics and researchers, including author John Creswell, delving deeper into research topics, concepts, and case studies. Watch the videos and check your understanding by answering the questions below. (Answers available on separate tab.)

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Problems with Reliability and Validity

Dr. Evelyn Behar and Dr. Mariann Weierich discuss threats to internal validity.

Research Design: The Experiment

Dr. Weitzman discusses designing quantitative experimental research studies.


1. Rae is conducting an experiment that randomly assigns individuals to a nature walking intervention or a control group to examine the effect on blood pressure. Which of the following would be a threat to internal validity?

  1. relatively small sample size
  2. choice of statistical methods
  3. sampling by non-probability methods
  4. some individuals in the control also walk frequently

2. Internal validity is concerned with ______.

  1. the generalizability of findings
  2. the validity of measures we used
  3. whether we can attribute effects to the independent variable
  4. the use of appropriate statistical analysis

3. Experimental research is often used to determine ______.

  1. the effects of a treatment
  2. trends in the population
  3. relationships between factors
  4. a complex understanding about a phenomenon