1) To allocate funding properly and appropriately. It stops researchers spending lots of money on investigations which may encounter problems. Also it helps to develop the areas of psychology that need to be developed,
2) To validate the quality of research. It establishes more accurate to inter-observer reliability. Additionally it makes sure that you are measuring what you set out to measure.
3) To suggest amendments and improvements. It allows researchers to get more accurate results as it eliminates potential problems.