Key Details Versus Interesting Extras

Separate details that support the central idea from details that are just interesting.

Not every detail in a text supports the central idea. Some are interesting extras: colorful facts, side notes, or background that makes reading enjoyable but isn't essential. Knowing the difference matters when summarizing or citing evidence. A key detail is one that, if removed, would weaken the central idea. Read this original paragraph: 'Sea otters protect kelp forests. They eat sea urchins, which would otherwise devour the kelp. Where otters disappeared, urchins multiplied and kelp forests shrank.

Otters also hold hands while sleeping so they don't drift apart. ' The central idea is that otters protect kelp. The first three details support it directly. The hand-holding fact is charming and true, but it doesn't help prove the point, so it's an extra. To sort details, ask: Does this help explain or prove the central idea? If you deleted it, would the argument be weaker? Leaving extras out of summaries keeps them focused.

• 1Key details directly support the central idea
• 2Interesting extras add color but aren't essential
• 3Test: would removing it weaken the central idea?