There is no doubt that some social issues make more engaging topics for research papers than others. However, it is beneficial to know the most common social issues. These include abortion, drug use and abuse, capital punishment, homelessness, homosexuality and immigration. What makes one social issue more relevant or appealing to write about than another is a subjective matter. However, the above topics have all caused widespread discussion and debate.
Certain social problems rear their heads with predictable regularity. From culture to culture, and age to age, this sub-set of human dramas simply won't go away. Issues such as these range from whether prostitution should be illegal, to whether homosexuals should be allowed to openly serve in the military. These recurring social issues make superb topics for research papers because they are likely to resonate with a great many people.
Homelessness is a social issue that directly affects a relatively small sub-set of the population, but the argument can be made that it affects everyone in one way or another. According to the United Nations, over 100 million people worldwide are homeless as of 2011. This social issue is a prime example of a problem that will resonate with a large audience. Further, there is a great deal of research already done on this topic. Far from making it difficult to find a unique angle to write about, this data will allow you to quickly determine what has already been done to excess.
Another good example of a topic that provokes an emotional response from readers is that of mental illness. A great many of the mentally ill feel as if their disease is merely a small annoyance, and that they are not truly ill. This creates a situation in which it is tempting for them to stop taking their medications. Hence, many mentally ill people who repeatedly refuse to take medication are hospitalized. This is the sort of hot-button topic that is both engaging and relevant, and therefore makes for an interesting topic for a research paper.