Archaeology is easy to do badly. It is usually the case that the same evidence fits multiple interpretations. The proper way to do it is to treat archaeology as a process of winnowing out theories as they are found to be inconsistent with evidence. The wrong way to do it is to pick a theory you want to be true and to show how to fit the evidence into that theory (especially because the temptation is strong to discard evidence that is inconvenient for the theory, hoping no one will notice).