Many people disagree on whether a particular fic is good or not, but generally, goodfics have certain agreed-upon characteristics.
Recognizing goodfic is a problem in some fandoms due to Big Name Fans, shipping wars, and established fanon. Some factions in a fandom might recognize a fanfic as a goodfic that other factions might consider a badfic due to themes and/or squickiness. Indeed, even the most blatant Mary Sue stories often receive dozens of glowing reviews from other Suethors. However, receiving no honest concrit does not mean a fic is good, and all goodfics are liable to be considered badfics by fandom factions who really only disagree with the preferences of the fic's author, which has nothing to do with good writing. Therefore, what fanfic you enjoy is largely up to personal preference, but a really ill-conceived, poorly-written fic will never be considered a true goodfic.
The PPC generally expects fanfiction to have the following characteristics in order to be called goodfic:
- Excellent characterization.
- Follows canon.
- Extrapolates from known canon while remaining believable for that canon.
- Correct spelling and grammar.
- Canon characters remain in character or follow a believable path from how they are characterized in the canon to how they end up in the fanfic.
- Believable original characters that do not break the story.
- Good AUs which offer believable narratives of the could-have-beens of the canon.
Certain goodfics that are very popular among the PPC are elevated to the status of Legendary Goodfic.