got a merciful hit from another forum. the answer looks so simple I'm almost embarased I had to ask.

app.project.flie.parent.parent

right now I'm using app.project.file.path which gives me something like this: say I have a project file at ~/desktop/my_project/ae_project_files and I want to create an 'output' folder in ~/desktop/my_project/ how would I programmatically select a directory one up from the one my project file is in?