Although the scope of your paper might seem overwhelming at the start, generally the narrower the thesis, the more effective your argument will be. Your thesis or claim must be supported by evidence. The broader your claim is, the more evidence you will need to convince readers that your position is right.
Example of a thesis that is too broad: Drug use is detrimental to society.
There are several reasons this statement is too broad to argue. First, what is included in the category "drugs"? Is the author talking about illegal drug use, recreational drug use (which might include alcohol and cigarettes), or all uses of medication in general? Second, in what ways are drugs detrimental? Is drug use causing deaths (and is the author equating deaths from overdoses and deaths from drug related violence)? Is drug use changing the moral climate or causing the economy to decline? Finally, what does the author mean by "society"? Is the author referring only to
Example of a narrow or focused thesis: Illegal drug use is detrimental because it encourages gang violence.
In this example the topic of drugs has been narrowed down to illegal drugs and the detriment has been narrowed down to gang violence. This is a much more manageable topic.
Qualifiers such as "typically," "generally," "usually," or "on average" also help to limit the scope of your claim by allowing for the almost inevitable exception to the rule.