1. Experimental Design I. Definition of Experimental Design
II. Simple Experimental Design
III. Complex Experimental Design
IV. Quasi-Experimental Design
V. Threats to Validity

2. Experimental Design - Definition
Control over the sequence and proportion of the independent variable involving: 1) at least two conditions (i.e. an independent variable); 2) random assignment of subjects to conditions; and 3) the measurement of some outcome (i.e. dependent variable

3. Experimental Design – Simple Designs
1. Post-test Control Group Designs (t-test)
E R X -> O1
C R > O2
2. Pre-Post-test Control Group Designs (t-test)
E R O1 X -> O3
C R O > O4

4. Experimental Design – Simple Designs (cont.)
3. Soloman Four Group Design (t-test)
E1 R X1 -> O1
C1 R > O2
E2 R O1 X1 -> O3
C2 R O > O4
4. Analysis of Variance (ANOVA)
E1 R X1 -> O1
E2 R X2 -> O2
E3 R X3 -> O3

5. Experimental Design – Complex Designs
1. Completely Randomized Designs (CRD) (This example is a 2x3 CRD)
  C-E1 C-E2 C-E3
R-E1 O11 O12 O13
R-E2 O21 O22 O23
Main Effects
Interaction Effects

6. Experimental Design Complex Designs (cont.)
Incomplete Designs (IRD)
Split Plot Design (This example is a 2x3 SPD)
C-E1 C-E2 C-E3
R-E O12 O13
R-E2 O21 O

7. Experimental Design Complex Designs (cont.)
3. Repeated Measures Designs (RMD)
Latin Square Design ( This example is a 4x4 LSD)
O1 O2 O3 O O2 O3 O4 O O3 O4 O1 O O4 O1 O2 O3

8. Experimental Design – Quasi Experiments
1. One Shot Case Study
E O1 X ->O2
2. Non-Equivalent Control Group Design
E O1 X -> O3
C O > O4
3. Interrupted Time-Series Design
E O1 O2 O3 X O4 O5 O6

9. Experimental Design - Threats to Validity
1. History = confounding of IV over time
2. Maturation = age / experience contaminate
3. Testing = subjects come to understanding IV
4. Regression to the Mean = extreme scores regress
5. Selection of Participants = non-random assignment
6. Mortality = subject attrition
7. Diffusion of Treatments = lack of control group