Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The linear no-threshold model (LNT) is a method for predicting the long term, biological damage caused by ionizing radiation and is based on the assumption that the risk is directly proportional to the dose at all dose levels. In other words, the sum of several very small exposures have the same effect as one larger exposure. The LNT model therefore predicts higher risks than either the threshold model, which assumes that very small exposures are negligible, or the radiation hormesis model, which predicts the least risk by assuming that radiation at very small doses can be beneficial. Because the current data are inconclusive, scientists disagree on which method should be used.