The phrase according to means “as stated by” or “as reported by” someone or something. When you write according to the weather forecast, you're telling readers where your information came from. When a news article says according to eyewitnesses, it's showing that the reporter got the story from people who saw what happened.

This phrase serves an important purpose: it lets you share information while being honest about its source. If you say according to my older sister, the math test will be hard, you're not claiming the test will definitely be hard. You're reporting what your sister said, and readers can decide for themselves whether to trust that source.

Scientists use this phrase constantly: according to the study or according to the data. Historians write according to ancient records. Even in everyday conversation, you might say according to Mom, we're leaving in ten minutes.

The phrase also appears in another sense: according to the rules means “following the rules” or “in agreement with the rules.” When a referee makes a call according to the rulebook, they're following what the official rules say. This usage shows up in phrases like according to plan, meaning things are happening the way they were supposed to.

Using according to makes your writing more precise and trustworthy because it shows you're not just making things up or presenting opinions as facts.