dear i think the most important cause of many people's failure is that they dont prepare in a well manner.

though they are almost all master yet they are master in only one subject whereas css requires mastry in 12 subjects. so it is bit difficult to aquire cammand over all these subjects.

besides, lack of guidance is another reason of many candidates failure in this prestigious exam.

likewise some conditions of fpsc, like to pass all compulsory subjects with 40%marks, optional with 30% marks and aggregate with 50% marks, may be the cause of many people failure in the exam. as is obvious from the result of 2008 in which many candidates could not secure 600 marks that is what total aggregate u have to acquire to be declared successful.

so there may be many other reasons but these are i think major causes of failure.