Research Designs

In the Causality post, I discussed the Solomon four group design. This design addressed some concerns on internal and external validity.

In this post, I will discuss other research designs, their advantages and disadvantages.

Nonequivalent Control Group Design

Advantages

  • Controls for the main effects of history, maturation, testing, instrumentation, selection and maturation.

Disadvantages

  • We do not test for the interaction between selection and maturation.
  • The problem of regression.
Counterbalanced Design
Advantages
  • This design has internal validity on all the individual points.
Disadvantages
  • There are systematic selection factors involved in the natural assemblage of the groups, as well as the effects associated with specific sequences of treatments.
Multiple Time-Series
Advantages
  • An extended version of the Time Series design and the Nonequivalent Control Group design, this model controls for all internal sources of validity.
Disadvantages
  • The only disadvantage is that we are not controlling for potential interaction of testing and selection with X.
Time Series
Advantages
  • Maturation is well controlled for (unless it is very abrupt), instrumentation is also well controlled for assuming we keep the same measures.
  • Regression, selection and mortality effects may also be ruled out.
Disadvantages
  • Failure to control history is the biggest weakness.
(Adapted from group and course notes)
(Flashcards and other resources here)
 
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