What is the meaning of tangible factors?

If something is "tangible" it means you can literally touch it. For example, objects are tangible - you can hold a cup, a piece of fruit, a book etc... Gases are considered to be tangible; you can still touch them even though you may not be able to "feel" or "see" them.

Intangible things are generally concepts, ideas, dreams, thoughts etc...

"Tangible factors" would mean the visible/touchable elements contributing to something.