Every important type of examination has to be prepared without mistakes. Can you imagine a situation in which, for example, A-level test has some mistakes that will effect the results of students. If that would happen a lot of problems will occur. That is why every test have to be verified in details to minimize the possibility of mistakes. People who are supposed to do that have very responsible job and they have to be focused while they are checking it. The same process is undertaken as far as Theory tests are concerned. Mistakes in those tests will not only influence the results of the people taking it but it may affect their future driving as well. If they choose the correct answer and still fail the test they will be really surprised and the driving center will have a lot of problems trying to explain that to them. I can assure that theory tests are checked vary carefully as I was responsible for that. It was my job for five years and that is why I know how does it look in details. Despite the fact that it was difficult and time consuming to go through all the questions I remember it as a good job that was well paid at the same time. All the questions are divided into smaller parts and then each set of questions is looked into by three different people. That guarantees that there will be no mistakes at all in theory tests.