In academic reporting when a statement is not cited, eventhough the statement may be true, it is viewed as an assumption. Although all research is based on underlying philosophical assumptions about what constitutes 'valid' knowledge and which research method/s is/are appropriate for the development of that knowledge in a given study, the researcher has to acknowledge where the knowledge originates from. To conduct and evaluate any research, it is therefore important to know what these assumptions are and how they relate to the knowledge base. The researcher therefore refrains from making assumptions without describing their relevance and providing proper citations in support of the argument, notion or concept. The discussions you have should be placed within the correct context of the argument you are proposing or should form part of the context, the background, or the research problem, of your research study or the questions you are hoping to address. You have to explain why it is important, how did you establish this, and what made you believe it is an issue. You cannot assume anything, you need to describe everything you say and support it by citing authoritative sources.
You have to ask yourself these questions: Why do I say this? Where did I get this statistic? Is it true? Be careful not to make assumptions, and think the reader knows less than you. Rather consult several authors, provide their respective definitions and then select the one that best suits your research argument. Explain your choice of decision. When you offer an argument/statement, you need to support it. If it is not supported, it would appear to be an assumption, and you should never make assumptions in academic work. Citations needed.
Leedy, P. D. & Ormrod, J. E., 2014. Practical Research: Planning and Design. 10th ed. Essex: Pearson Education Ltd.