How to write summaries
Write like the lead sentence in a hard news story.
Last modified: 6/1/98
The lead sentence in a newspaper story is a good example
Newspapers are a good place to learn about writing summaries. The first sentence or two of a newspaper story is often called "the lead". The lead sums up the story. It tells you what is covered in the story, giving you the basic information and letting you know what you can expect to find if you read further. The goal is to be short, but not too short.

For example, in a story entitled:

"Acme buys Zenith"

a good lead could be:

"Acme Industries, the top player in the widget field, announced today that it was purchasing Zenith Associates, its major competitor, for $150 million in cash."

Notice how much useful information is presented in a clear and concise manner in this lead. You can see that the scope of the article is the announcement, it is not the reaction of others. You can understand that the position of the players in the industry is important.

A poor lead could be: "People are talking and $150 million is a lot of money. That's what the people of Acme paid for Zenith. (Zenith Associates, not the one in consulting.)." This lead is not clear and concise. We miss the time it happened (today), the formal names, their relative positions in the industry, the fact that it was cash and not stock, etc. Questions are brought up: Is this story about the amount? It is about who bought who? It it about the reaction?

The concept of well-written leads can help in writing summaries for web pages:
•   The lead can be the start of the page, letting the reader know right away what they will find.
•   It could be in a subhead above the scroll, perhaps in a side border.
•   It could be at the link site, letting the reader know what they would get if they clicked.
•   It could be a combination of these.

Length depends on use
The length of the summary can vary depending upon the use, but the concepts used in writing leads still hold.

Write the summary last
Write the summary after you've written what it is summarizing. This is often much easier than writing the summary first. If you find writing the summary first is easier, make sure that you check it after you write the rest to make sure it is still an appropriate lead.

Good and Bad Summaries

Good Bad
The effect of localizing the effects of any errors is the prime benefit of the curing technique used by this manufacturing process. See why the manufacturing technique is special.
(Doesn't tell you why -- it's a tease)
The troubleshooting functions cover only a subset of the common errors in this type of product. This product is designed to cover Alpha, Beta, and Gamma versions. Beta errors are detected. Alpha, the more likely, is not.
(Not concise enough, and the conclusion is not spelled out)
We recommend doing the acquisition because it will save us money. It's good to save money in these hard times.
(Not the main point)

This site is filled with many other examples.

See also: "How to write titles".