There are simple charts or graphs (one such example is at this link), but the word "simple" does a disservice to deciding whether to use LPTA or trade-off to make a source selection decision. I assume you already reviewed FAR 15.101 for proper use of the two methods. However, it's also essential to review Appendices B and C of the DoD Source Selection Procedures, which discuss the two methods in detail. It's also important that your team consult DFARS 215.101-2-70, which adds recent restrictions to the use of LPTA resulting from the NDAA for 2017.