SOURCES OF INTERNAL INVALIDITY

IN RESEARCH DESIGNS

Taken from Campbell and Stanley

History
Maturation
Testing
Instrumentation
Regression
Selection
Mortality
Pre-experimentalDesigns:
 
            
  1. One Shot Case Study

    2. X O
_
_
 
  
 
_
_ 
  • One Group Pretest/Posttest Design

    • O X O
    _
    _
    _
    _
    ?
    +
    +
  • Static Group Comparison

    • X O

    - - - - - - -

                         O
    +
    ?
    +
    +
    +
    		 _ _
    True Experimental 
    Desgins
    		              
  • Pretest/Posttest Control Group Design
    • R O X O

                  R O    O
     

    +
     

    +
     

    +
     

    +
     

    +
     

    +
     

    +
  • Solomon Four-Group Design

    • R  O X O

    R  O     O

    R    X O

    R       O
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +
  • Post-test Only Control Group Design

    • R X O

    R     O
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    +

     

     

    Quas-Experimental Designs:
    History
    Maturation
    Testing
    Instrumentation
    Regression
    Selection
    Mortality
  • Time Series

    • O O OXO O O O

    		 _
    +
    +
    ?
    +
    +
    +
  • Equivalent Time Samples Design

    • X 10 X0O X1O X0O, etc.
    +
    +
    +
    +
    +
    +
    +
  • Equivalent Materials Samples Design

    • MaX1 O  MbX0  O  McX1 O . . .
    +
    +
    +
    +
    +
    +
    +
  • Nonequivalent Control Group Design

    • O X O

    - - - - - - - - - - - - -

    O     O
     
     

    +
     
     

    +
     
     

    +
     
     

    +
     
     

    ?
     
     

    +
     
     

    +
  • Counterbalanced Designs

    • X1O X2O X3O X4O

    _ _ _ _ _ _ _ _ _ _

    X2O X4O X1O X3O

    _ _ _ _ _ _ _ _ _ _

    X3O X1O X4O X2O

    _ _ _ _ _ _ _ _ _ _

    X4O X3O X2O X1O
    +
    +
    +
    +
    +
    +
    +
  • Separate Sample Pre-test-Posttest Design
    • R O (X)

    R X O
    _
    _
    +
    ?

    +

    +

    		 --
    12a. R O (X)

             R     X     O
    _ _ _ _ _ _ _ _ _ _

    R                      O (X)

    R                       X O
    +
    _
    +
    ?

    +

    +

    		 _
    12b. R     O1 (X)

             R       O2 (X)

             R        X       O3

    		 _
    +
    +
    ?
    +
    +
    _
    12c. R O1 X O2

            R X O3

    		 _ _
    +
    ?
    +
    +
    		 +

    _ Indicates a weakness in the design

    + Indicates that the factor is controlled

    ? Indicates a possible source of concern

    A blank indicates that the factor is not relevant

    IMPORTANT!! Do not assume the chart is correct until you have carefully read the study. Use this chart as a guide to help you evaluate the validity of quantitative studies.
     

    3 questions to frameIresearch is/notI quantitativeIqualitativeIabstractingIknowledge claimsI asumptionsI

    sources of internal validityI criteria for critiqueI