A thesis is written with a motive of answering a specific question or offering a solution to a chosen problem. Such question or issue has to be stated in your abstract, introduction, and in some cases, also in the literature review chapter. The aim of stating such question is to give a clear idea to your reader about the core theme of research and its direction. So, to meet its goal, the question must be as unambiguous as possible. It may take time to write a question that is not complex. This is because while you may be familiar with the issue and understand what you seek to study, readers may not grasp your meaning.
Apart from clarity, the question must also have focus. A general question, or one with a wide scope, will create problems for you. A specific question will provide a direction to your research and help you stay away from a bulky, generalized report. Knowing from the very beginning what you want to explore is critical. It will also enable you to define your reader base and get the paper published.
In most cases, a good research question will begin with ‘how’ or ‘why’. You can have a ‘what’ question, but in very limited cases; for instance, when you are studying the effects of certain chemical reaction, or exploring the root cause of an event. ‘What’ and ‘when’ questions can confine the scope of your study and make your report a compilation of facts and figures, rather than a description of research process. With ‘how’ or ‘why’ questions, you will have better scope for original research and discussion. It is important for meaningful critical analysis of the information that you gather.
In fact, a clear research question will lead you to accurate data as well. Without knowing what exactly you want to find out, you cannot prepare good questionnaires. Work on your research question and revise it several times to attain perfection.