They do not provide accurate dates of their alleged data, and there are many other things wrong with it. (religion.blogs.cnn.com)
Full members can performed an advanced search to get more accurate dates, as they can have 40 search definitions to choose from. (wantmillionaire.com)
Some tests claim to give accurate dates a few days before a missed period, but most will work better one to two weeks after a missed period. (mommyedition.com)