Clinical judgment and sometimes ethical judgment enter into these decisions where there are often no right or wrong answers and where there are no textbooks or RCTs that tell us what to do.
predecessor - something that precedes and indicates the approach of something or someone. harbinger, herald, forerunner, precursor. indicant, indication - something that serves to indicate or suggest; an indication of foul play; indications of strain; symptoms are the prime indicants of disease.
A prequel is a literary, dramatic, or filmic work whose story precedes that of a previous work, by focusing on events that occur before the original narrative. A prequel is a work that forms part of a back-story to the preceding work. All prequels are, by definition, essentially sequels in that they expand on a previous or preceding work.. The term is a 20th-century neologism that is a portmanteau of the prefix pre- (from Latin prae, before) and sequel.