I am interested in making some graphs to portray 4 different research
designs: Randomized experiment, regression discontinuity design,
instrumental variable design and matching on observables design. These are
all economic models. Basically, all I need is just conceptual graphs to make
it easier to understand the theory behind them. So, I don't have any data
available. Would anyone know how I could do that in excel. I appreciate
your time and help very much. Look forward to hearing from you.

Sincerely,

Ledi