Modal estimate when it comes to project deadlines

Question

I'm relatively new to Project Management (having a technical background) and I noticed that there are these specific columns in an excel file regarding deadlines:

Pessimistic | Optimistic | Modal | PERT | Actual

Can someone give me an overview of what these mean (specifically, Modal and PERT) or provide a link to where I can read more about these?

Answer 1

PERT is a weighted average of Optimistic (O), Pessimistic (P) and Most Likely (M) estimates:

(O + P + 4 * M) / 6

Check the cells under PERT to see if they have this formula. Probably "Modal" is the "Most Likely" estimate.