With respect to the amount of research that's done to bring a product to market, it is very extensive. For instance within our environmental assessment directorate, an evaluator or a team of evaluators would be looking at literally hundreds of studies and tens of thousands of pages of data.
The registrants are required to provide not only summaries of the experiments or the research, but also all of the raw data. Then our scientists independently go through all that information and decide whether they agree with the conclusions of the manufacturers or not. If they don't, then we change the conclusions to suit what our scientists feel the science says.