I work with the PHAA, Susquehanna Valley, and Mason-Dixon Diploma Programs for highschoolers in Pennsylvania. Each program has a unique niche and slightly (or dramatically) different requirements. Most of the differences have to do with what is required for English credit each year. In order to keep it all straight myself, I created a table summarizing the differences which you can download here and print or use for comparison.
The law requires all teens to have 4 credits of English, 3 of Math, 3 of Science, 3 of History, 2 of Arts and Humanities, and 2 “other” electives. Each of the diploma programs require those courses and have other requirements unique to their program.
PHAA has been around the longest and set the standard for homeschool diplomas. They require teens in grades 9-12 to read 25 books each year (3 of which need to be classics), write a 10-page paper (2500 words or more) as well as 3 other shorter compositions, and give one speech to an audience outside the family. In other subject areas their requirements match what the law dictates.
The main advantage of the Mason-Dixon diploma is that a student may request a Diploma with Distinctions in art, music, drama, or academics. If a student is investing a good bit of time and energy in one of these area, this diploma will help highlight that achievement. See the chart above for more specifics.
If a student has a unique situation, or has come to homeschooling late, or for any reason has not been able to meet the requirements of another diploma program, I have found Susquehanna to be very helpful and understanding. Their goal is to make sure that every student who has finished high school can get a legitimate diploma.
If you have questions about them, let me know and I will try to help.
I created a page with contact information and website links for each of the diploma programs.