Facts that will be relevant to any debate, and consequently persuasive, are usually recent facts.
Unless you are debating some historical aspect of the topic, then using sources from several decades ago will make you seem to your audience as a lazy or inept researcher.
Most of the library's databases are set up to default on relevancy ranking for their results lists. However, you would be well served, in most cases, to change this to 'Date Newest' so that you will see the most recent content at the top of the list.
The requirement for this debate is to choose at least 3 scholarly sources from which you will find your facts.
Dr. Perkins emphasized "at least" for a reason.
Ten years from now you need brain surgery.
Surgeon A - "In my debate assignment in medical school I found three fairly decent scholarly articles and built my debate outline from those."
Surgeon B - "I was very selective and only wanted the most recent and pertinent articles, but I still ended up with about ten of them because I spent a lot of time searching and even consulted with a medical librarian to ask for help. I understood that there is such a thing as a reputable information source that wasn't peer reviewed, so I was equally selective and included those as well. My outline was the result of a careful effort on my part to get the best most relevant information that I could find. I certainly didn't stop at just three articles. I wanted to win the debate but also learn everything I could about it."
QUESTION 1: Which one of these surgeons do you want cutting into your head?
QUESTION 2: Read the first 7 paragraphs of the brief article below. Describe a hypothetical situation in law enforcement in which a lazy, shabby job of information retrieval could result in serious injury or loss of life and point out any similarities between your hypothetical scenario and the reality of what happened to Ellen Roche.