Appearing for CAT without taking a mock is similar to driving a car for the first time on a busy road without any practice. For a novice, the complex operation of driving coupled with the confounding environment on road will make the task insurmountable. Unlike GMAT or GRE, CAT is a non-standardized test which means it may not follow the same pattern every year. In fact, CAT is known for its changes which come as a surprise to many a aspirant. Add to that, the complex nature of questions from three diverse sections which make cracking CAT with little or no practice almost impossible.
In CAT prep, mock test is an effective way of evaluating your present standing vis-a-vis other aspirants. Mocks help you get familiar with the test and let you formulate effective test strategies. Therefore, it is advisable to start taking mocks a few months before the D-day so that you get sufficient time to experiment and fine-tune your test strategy. Completion of the concepts by the time mocks begin is not a necessary condition to start taking mocks.
A common question from students is “From when should I start taking mocks seriously?” The answer is from the first mock, irrespective of your preparedness. Take the initial few mocks to get comfortable with the exam and to develop a good focus. In an intensive exam such as CAT where speed and accuracy determine success, staying focused for 3 hours at a stretch is very essential. You need not take your percentiles from first mock at face value. You will take at least 3-4 mocks to attain a level of comfort which reflects your true performance. Also in some cases, the syllabus may not be fully covered when mocks kick-in which can limit your attempts. Try to take a mock every 10 days from now till August. Thereafter in the last 10 weeks to CAT, one needs to take at least 2 mocks per week.