Executive Summary
An executive summary is written to an audience that is reading the summary to better enable them to make intelligent and informed decisions. The memo should be formal, even if the person it is directed to is a friend or long time associate.
The author of the summary should keep in mind that the executive may be making decisions that will impact social, economic, and or environmental impacts on the community at large. The public's safety and welfare may be impacted by the decisions an executive makes based on the content of an executive summary. Therefore, all information contained in the summary should be factual, or if an opinion is expressed, it should be based on reproducible experimentation or analysis. It is the ethical responsibility of an engineer to report factual and accurate information.
Executives are more concerned with the impact of the data or analysis than they are the specifics. So, executive summaries should be succinct and to the point. Your analysis must have credibility and you must convince the executive that your summary contains accurate, factual information. Keep in mind, your summary may ultimately be used to protect you and/or your company from liability in a court of law. (You should keep copies of all correspondence!)
It is your professional responsibility to clearly indicate any concerns that you may have based on your analysis and to point them out in the summary--even if it may not be what the executive wants or expects to hear.
You should close your summary with recommendations based only on observed facts or thorough and accurate analysis.