We have different boards in this forum and from the past merit source applications I have seen they usually direct their application to a certain board that lacks merit.
Those that are made merit source are they assigned to distribute merit to a particular board or they are not assigned to any board.
There are both: during application, a few applicants used a specific board's reference where they had been active, and a few haven't used any specific board. But after approval for merit sources, they are free to spend their merits anywhere. But to me, priority should be there and used during application. But I don't think theymos minds even not being active there.
Why I’m asking this question is because boards like Economics, trading and political & society boards are actually lacking merit distribution meanwhile there are good threads created by members.
So does the forum management assign merit source to a particular board or not?
As I said above, assigned. But depending on the merits of the sources, they might move into other boards as well. But are you sure your mentioned boards have any specific merit sources? I don't think merit sources are moderated by the forum admins unless there are any allegations raised against merit sources.
However, if you believe there are some posts that deserve merit, then you may mention them in merit threads. So merit sources would take a look at that.