Write the supporting section that covers the background and details of the problem. When you are finished, make sure that you can identify the problem statement. Have a friend read the background section and see if he can identify the problem statement. If you both can easily find the problem statement, then it is appropriately stated. If not, rewrite it so that it is more clear or so that it fits the information more closely.
Examine your problem statement in detail. Is the listed problem too large for the scope of your report? For example, if you are writing a proposal covering the problem of the lack of sufficient parking at your university, if you covered all parking areas on campus, that problem would be too broad for a two-to-four-page proposal. Instead, narrow your problem statement to one parking lot on campus.
Decide whether your problem statement is too narrow. Are you covering enough of the problem to enable the audience to understand the situation? For example, if you are writing a research paper about the causes of rural poverty, just covering farm income and subsidies would not represent all people in rural towns. In that case, you would need to expand your scope by detailing at least the top three causes of rural poverty to sufficiently cover the problem.
Write the paper. If your paper is too long or if you find through research that your problem statement is too broad or complex, narrow it. If you do not have enough information, expand the problem statement to include more detail.
Examine the finished paper. Does your problem statement still match the contents, or did you find that your problem was more complex than you had originally thought? If the problem statement has changed, revise the statement.