When using a pressure cooker at 15psi, the cooking time for a recipe should be one-third what is given for cooking it on the stove top or in the oven. Time is not the only element of a recipe to adapt for a pressure cooker.
Since a pressure cooker is a closed system, there is little to no evaporation of liquids during cooking. Less liquid is required in preparing a pressure cooker recipe to produce a result that is similar to an equivalent stove-top recipe. However, pressure cookers come with instructions regarding the minimum liquid to be used for cooking.