- I don't see sufficient conceptual difference between ARCH and GARCH models to maintain both tags.
- GARCH is more general, so I suggest keeping garch as the tag name to remain.
- arch has 41 questions while garch has 292; only 11 questions are tagged with arch without garch.
- I have checked the questions tagged arch without garch and I do not see that they would be sufficiently special to deserve a separate tag.
If the community agrees (we will see), how can this be done? It would be nice to get rid of arch in a way that it would not reappear soon thereafter and there would not be a need to raise the question again.
Edit: vote here in the thread for suggested synonyms.