Pestel and Porter's 5 forces model

It depends on the information given in the question. If there is no information about any of the 5 forces, you can't use that. However the use of PESTEL and 5F are not mutually exclusive. For example, the decision to go into a new country will depend on economics, laws and politics there but will also depend on entrance barriers and competition. Remember, if you aremusing either of these models, you do not have to go through every initial or force. A qiestion might talk about social, technological and economic matters amd say nothing about politics, the law or environmental issues. In which case just talk about S, T and Econ and stay silent on the others.