Skimming and Scanning: Reading Faster With Purpose

Two techniques, two different goals

Not everything you read deserves the same attention. A chemistry chapter you must master calls for slow, careful reading. A long report where you need one number does not. Skimming and scanning are two ways to read quickly with a particular aim. They are often mentioned together, but they do different jobs.

• Skimming means moving quickly through a text to understand its general idea and structure.
• Scanning means moving your eyes over a text to find a specific piece of information, such as a name, date, term or answer.

Neither replaces careful reading. They help you decide what to read carefully and save time on what you do not need.

Skimming: getting the big picture

When you skim, you are asking, “What is this about, and how is it organized?” You do not read every word. Instead you sample the parts of a text that carry the most information.

A typical approach:

1. Read the title and any subtitle. They often state the topic or the main claim.
2. Read the introduction or first paragraph. Many texts say what they will cover.
3. Read headings and subheadings. Together they act as an outline.
4. Read the first sentence of each paragraph. In a lot of writing, this sentence introduces the paragraph’s point. This is common but not universal.
5. Look at visuals. Charts, tables, images and their captions can summarize key points.
6. Read the conclusion or final paragraph. It often restates the main findings.
7. Notice bold or italic terms and any lists.

At the end you should be able to say in a sentence or two what the text is about and what its main parts are. If you cannot, the text may not be well organized, or you may need a second pass.

When skimming is useful

• Deciding whether an article or book is worth reading.
• Previewing a chapter before reading it closely, as part of reading textbooks.
• Reviewing something you read before, to refresh your memory.
• Getting the outline of material when time is short.
• Checking several sources to see which is most relevant.

Scanning: finding a specific detail

Scanning starts with a clear target. You are not trying to understand the page, just to locate something on it. Think of looking up a phone number or checking when a meeting starts.

A typical approach:

1. Decide exactly what you are looking for. Hold the keyword, number or name in mind.
2. Predict where it will be. A date might appear near a heading or in a table. A definition may be in bold.
3. Move your eyes quickly down the page, often in a vertical or zigzag pattern, without reading full sentences.
4. Watch for the cue. Capital letters, digits, bold terms or particular words can stand out.
5. When you find it, slow down and read the surrounding sentences to be sure it answers your question.

On a screen, the browser’s search function can do some of the scanning, but you still need to read the context to make sure you found the right thing.

When scanning is useful

• Finding a fact in a long reference text.
• Locating a formula or definition when revising.
• Checking an index, table of contents or timetable.
• Finding the part of a source that relates to a question you are researching.
• Looking up instructions or settings.

Choosing between them

Ask what you need from the text.

Many tasks use all three in order. You skim to get oriented, scan to find the relevant part and read that part carefully.

What speed reading claims get wrong

You may see advertisements promising to multiply your reading speed several times over. Be cautious. Research on reading generally suggests that when speed rises sharply, comprehension tends to fall. Skimming and scanning are legitimate because they change what you do, not because they make you absorb every word faster. You are choosing to read less, deliberately.

This means that skimming gives you the gist and may miss details, nuance and qualifications. For material where accuracy matters, such as exam content, medical or legal information, or a text you plan to cite, read carefully. Skimming also should not be used on arguments you want to judge, since it is easy to miss reasoning when you only sample the surface. Judging a claim fairly goes hand in hand with careful source evaluation.

Habits that help

Set a purpose first. Write down your question before you start. A clear aim makes your eyes find what matters.

Use the text’s structure. Well-organized material gives you signposts: headings, topic sentences, lists, summaries.

Avoid subvocalizing everything. You do not need to “say” each word in your head when skimming, though forcing this is difficult and not always useful. Focus on keywords instead.

Make a note. After skimming, jot a quick summary or a few questions. This turns speed into something you can use.

Stay flexible. If you reach a passage that matters, stop skimming and read it properly.

Practicing

You can practice with news articles, long emails or textbook chapters.

• Set a time limit of two or three minutes to skim an article, then write what it was about. Read it fully and see how close you were.
• Practice scanning by choosing a question, such as “What year is mentioned for the first event?”, and finding the answer as fast as you can in a page of text.
• Use a table of contents or index to locate a topic and then check that the page really answers your question.

Over time, you get better at noticing structure and cues. You will also get better at judging when a quick pass is enough and when it is not, which is the real skill behind reading faster with purpose.