1. What is Solomon Four-Group Design and where is it mostly used?

2. What are the assumptions of Solomon Four-Group Design?

3. What are the strengths and weaknesses of Solomon Four-Group Design?

4. What are the threats to internal and external validity of Solomon Four-Group Design?

5. Analyze Solomon Four-Group Design in terms of appropriateness, assumptions, strengths and weaknesses, and threats to internal and external validity

6. Provide references less than 5 years old