Describe the three designs, and when is it appropriate to use each design? How are the designs similar?

Describe the three designs, and when is it appropriate to use each design?

How are the designs similar?

How are the designs different?

What specific methods are related to each of these designs?

References:

Robson, C., & McCartan, K. (2016). Real world research. Chichester, England: John Wiley & Sons.