Varying the length of your sentences in a paragraph and in a paper can make your writing more interesting and engaging for the reader. You can emphasize an idea with a short sentence or better explain a complex idea with a long sentence. But be careful! Too many short sentences and the paper becomes choppy. Too many explanations in a long sentence and it becomes a run-on. And always watch out for fragments!
Like prior knowledge and personal experience, risk assessment is another factor that must be taken into consideration. Trusting a person or institution until they provide evidence that one should not is fine in cases where the risk level is acceptable. If one orders a cheeseburger with bacon and trusts that the restaurant will make it that way only to find that the cook puts on lettuce and tomato instead, this is a minor problem. The cook was trusted to follow orders, but did not; the customer did not get what they ordered. The risk is minimal. But not all cases involve minimal risk. Sometimes the risk is too great to wait for proof. What then?
Long Sentence: The sentence is used to explain what the paragraph will be about.
Long Sentence: The sentence is used to describe the situation.
Short Sentence: The sentence is used to emphasize an important point.
Short Sentence: The sentence is used to transition to the next idea in the next paragraph.