Here are a few nuts and bolts suggestions on writing policy memos.
The memo should present all of the key findings of the analysis.
It should be no longer than necessary. Don't leave important things out but don't write a paragraph when a sentence or two will do.
It's very important to policy makers to know who would be helped and who would be hurt by a proposal.
Wherever possible, the memo should include all the facts a policy maker would need to reach her own conclusions and should not emphasize your personal opinion.
The main place where you can express your opinion is on whether the policy is a good means for achieving its goals. Does it work well or are there better alternatives? Avoid focusing on whether the goal itself is good or bad.
A table can often be worth a thousand words. It's a much faster way to present a set of numbers than to include them in the text and it can be a lot easier for a reader to understand. That's especially true when you need to show results for different demographic groups.
Focus on stating the facts and try to avoid including too many adjectives that might overstate your case or suggest that small differences are more important than they are. For example, don't say a policy imposes "huge" costs or creates "enormous" benefits unless the costs or benefits really merit the adjectives.
They generally aren't appropriate in policy memos.