What is the difference between a hypothesis and a research question?  I suppose some will ask: “Why should I care?”  

The answer is that knowing the difference is a clue to how strong the research findings are.  Experimental studies that use hypothesis create stronger evidence for practice, than do non-experimental studies that merely answer research questions.

• A hypothesis is a predicted answer and focuses on cause-and-effect , such as “Those who take 80mg ASA every day will have lower incidence of MI’s than those who do not.”  When we know a lot about a topic already, then we can hypothesize (in other words make an educated guess about how the experiment will turn out).  A researcher may word the hypothesis in interrogative form with a question mark, but you can still recognize it as a hypothesis if it uses any terms like cause, effect, impact, increase, improve, or their synonyms and has at least 2 variables.
• Researchers ask only a research question when they don’t know enough to guess about the cause and effect, & so they either 1) want merely to describe something or 2) to figure out whether 2 things are related to each other, but aren’t ready to identify one as causing the other. For example no one knows which came 1^st, the chicken or the egg?—you can see that chickens and eggs are related 100% of the time, but you may win a Nobel prize if you can figure out which one originally caused the other.

Cause and effect (experimental, hypothesis) studies create stronger evidence for practice than do descriptive or correlational (non-experimental, question) studies.

Critical thinking question: One of the following is a hypothesis & one is a research question.  Which is which and why?

1.  The purpose of this study was to describe the expectations for pain relief of patients with abdominal pain and how their communication with providers relates to their overall pain relief. (Yee et al 2006)
2.  We investigated whether a brief pain communication/education strategy would improve patient pain communication skills. (Smith et al, 2010)