Think of the last article you wrote for an international journal or conference materials. Now imagine how you would write the same article if the audience was made up of a group of intelligent children at high school level. Clearly, you would have to give more in-depth explanations of concepts, define more terms and take smaller steps as you move though through your arguments.
It’s quite easy to tell the difference between articles written by doctoral students and professors. One will spend half a paragraph describing the theoretical basis of PCR while the other will focus on the results. Either approach can be correct depending on the audience, and I can help decide which one is better.