The process of matching lighting fixtures inside of a home is very subjective and there is no precise answer. However, it is good practice to match some aspect of the fixtures from one room to another if the two fixtures are visible from different locations in the home.
It is good to match the general style, which means matching the basic lines, shapes, colors and textures of one fixture with the same design details of another. This is subjective, and the best method for achieving a solution is to find one fixture that you like, and then look at other fixtures with similar characteristics. They may even have different styles, but if the lines, shapes, colors and textures are similar, then it can work.
One good way of doing this is to visit an ALA-member lighting showroom and let a lighting consultant help you find fixtures appropriate for both locations.