Aldo is right. Most newspaper writing provides a good guide. The first paragraph – the first 2-3 sentences – should say immediately what is the key finding, to grab the attention. Then say why the research was done and how etc. An effective executive summary should read like a good press release.
As its name suggests, an executive summary summarizes, or reviews the main points of, a longer document or report for a reader that does not have time to read the entire report. An effective executive summary analyzes and summarizes the most important points in the paper or report, and will often make a recommendation based on the analysis. Executive summaries are “stand alone” documents that are almost always read independently of the reports they summarize.
You may submit an executive summary as part of an assignment, and your instructor will likely read the summary and the paper or report. It’s helpful, however, to keep in mind that executive summaries should inform and influence people who will only be reading the executive summary. Most of the time, you will be summarizing a paper or report that you wrote, but there may be times when you will write an executive summary of another author’s report or article. Often your instructor will specify the length of your executive summary, but 10% of the document that you are summarizing is a good rule of thumb. For example, a ten-page paper or report would require a one-page executive summary.