At risk is a prepositional phrase in which risk is a figurative location, as is "at peace." You are "at risk" when you are in a continual state of risking some sort of harm. Adding a hyphen, "at-risk," transforms the phrase into an adjective or a descriptor, meaning that the noun (the person or thing) it is modifying has the property of being at risk. "At-risk" often gets used this way because it is considered neutral — it expresses no judgment toward how the group that is at risk got to be that way, which is important when trying to help people. This is preferred to more colourful terms (e.g. "impoverished") which, in English, often carry a weight of moral disapproval. Do you agree with the addition of the hyphen ("at-risk")? Why or why not?