What are the factors that affect the random caps reward from production collection in Fallout Shelter?

Solution 1:

There are three factors.

Luck, luck, and luck.

Luck determines how many caps wasteland explorers get, and how many caps you get for successfully rushing a room's production. I believe, however, that the caps you get from leveling up a dweller is not affected -- they provide caps equal to their new level. Reach level 4? That's 4 caps. Obviously if you have 200 level 48 dwellers, you'll be raking in the dough soon enough.