Heh I remember asking this question a couple of years ago when I was newer and having a great deal of trouble getting any kind of rule oriented answer I have a vague recollection that I found something I could point to but if I did I can t find it now Then after a while I realized it was fairly standard at least for experienced editors to remove pre production films from tables so I just forgot about it and automatically do it I see people cite to WP CRYSTAL but that of course doesn t specifically address filmographies so it s a much more generalized and fluid concept and ultimately a judgment call Some even cite to WP NFF even though it s a notability guideline for the notion that if you can t have a film article about a film that isn t in production you can t have an entry in a film table either Not altogether satisfying as someone may always point out that notability doesn t affect content just creation I keep thinking that if I search hard enough I ll find something but the closest I came was a discussion I was involved in with no good answer from WP FILM Sorry If you do find anything please let me know I of course will do the same