Appropriate interviewing for a worldwide search.

jellomizer writes: I am a manger of a small Software Development department, looking to hire some more developers. By edict of the CEO the search must be made globally. So we are dealing with different cultures and different ideas of truth and embellishments, etc... To try to counteract we give the potential employees tests where I watch what they do, to see if they actually know what they say they know. However it seems a lot of applicants drop out when mention that this test is mandatory. Is this a sign that we caught them in a lie, or are we weeding out good people where we shouldn't be? Would you be willing to take a test as part of the interview, if so is there any type of heads up you would like to know beforehand to make a decision to take the test easier?