However, once a reproducing hazard enters the importing country, it may be impossible to contain. At that time, a specific sub-discipline for biological agent risk assessment did not exist. In the early 1990s work was begun in several countries to develop approaches and methods for biological agent risk assessment. Since that time, variety of methods, both qualitative and quantitative have been developed. There is much confusion about the nature and uses of science and of risk assessment.
Science proceeds by establishing an hypothesis and trying to discredit it.
Following numerous tests of the hypothesis, if it cannot be disproved, it is accepted as part of the factual body of science. Basically science is a very conservative and time-consuming process which demands high level of proof to establish a fact. The goal is to advance our understanding about phenomena in nature. Risk assessment is not science. Risk assessment structures the best available scientific and other relevant information to make decisions about hazards.