well, 1. i dont know how religion tries to predict anything, unless you want to include those guys who calculate when the world will end by dividing the number of vowels by the amount of times the name of the book is mentioned.
To call i astrology is saying theres a room of people who just randomly assign meaning to certain things
Liken it more to physics. We have general ideas where the electron will be at given moment, but we can't know for sure. And we're still trying to figure out quarks.
Psychology has the same difficulty in controlling variables as everyones mind is different. However, there are many things you can still prove as more or less true, like getting shot in one lobe may impair vision or cause a personality change. The same general rules can be applied to economics like price ceilings will lead to shortages. You then use these relationships and trends to determine the effect any action will have on an economy