Skimming and Scanning: When to Use Each

Two different goals

Students often have far more to read than time to read it. Two techniques help you cover a lot of text quickly, and they are easy to confuse because both involve moving your eyes fast.

• Skimming means moving quickly through a text to get the general idea: what it is about, how it is organized, and roughly what it concludes.
• Scanning means moving quickly through a text to find one particular thing, such as a name, a date, a number or a keyword, and ignoring everything else.

The difference lies in the question you start with. When skimming, you ask “What is this about?” When scanning, you ask “Where is this specific thing?” Choosing the right mode saves time, and using the wrong one wastes it.

Skimming: getting the gist

When it helps

• Deciding whether a source is relevant before investing time in it
• Previewing a chapter or article before reading it properly
• Getting an overview of a topic you have not met before
• Reviewing something you have read before and want to refresh
• Sorting a pile of articles for a research project

How to skim

1. Read the title, headings and subheadings. In a well-organized text they give you the outline.
2. Read the introduction and conclusion. Authors often state the main point and the plan early and summarize at the end.
3. Read the first sentence of each paragraph. In many texts, that sentence states the paragraph’s topic. Not every writer follows this pattern, so treat it as a tendency.
4. Look at visuals. Charts, captions, bold terms and boxed text carry condensed information.
5. Let your eyes drift over the rest. Stop only if a word or phrase signals something important.
6. Pause and summarize. Ask yourself what the text says in a sentence or two. If you cannot, the skim may not have worked, or the text may be too dense for this approach.

What skimming cannot do

Skimming gives you the outline, not the understanding. You will miss nuance, evidence and reasoning, and you may misjudge a text whose main point is hidden or subtle. It is a good first pass and a poor substitute for careful reading when the material matters for a test or an essay. It is often a stage in a longer approach to reading, such as the survey step in textbook reading.

Scanning: finding a detail

When it helps

• Looking up a date, name or figure in your notes or a reference
• Finding the part of a chapter that covers a term from a question
• Checking a quotation or locating a reference
• Finding a particular answer in a long page of instructions
• Looking for a keyword in a long document, which is also something a search tool does for you

How to scan

1. Know exactly what you are looking for. Hold the word, number or phrase in mind. If you are looking for a date, remember what digits look like on the page.
2. Predict where it will be. Use the layout: an index, headings, bold terms, a table, a glossary.
3. Move your eyes in a pattern. Run them down the page in a zigzag or a vertical sweep rather than reading line by line.
4. Stop when you spot it. Then slow down and read the surrounding sentence or two carefully to confirm it is what you need and to understand its context.
5. If you do not find it, try a variant. The text may use a different word, abbreviation or spelling.

What scanning cannot do

Scanning finds a detail but gives no sense of how it fits into the argument. A figure taken out of context can be misleading, so read the lines around it. It also depends on your being clear about what you need.

Putting both to use

A common workflow for research or an assignment looks like this:

1. Scan a list of sources for titles and keywords that match your topic.
2. Skim the likeliest ones to decide which deserve serious attention. When using web pages, skim with a questioning eye, and consider website reliability before using anything you find.
3. Read the best sources carefully, taking notes.
4. Scan your notes later when you need a specific fact for a draft.

This is a good way to use online resources without getting lost in them, and a good way to avoid reading everything with equal effort.

In exams

Both techniques have a place in exam preparation and on the day.

• Before writing an essay in a test, skim the whole paper to see how many questions there are and which you will tackle. This supports time planning.
• When a reading passage is followed by questions, a common approach is to skim the passage for the gist, then scan it for the details each question asks about. Check the instructions first, because the best tactic varies by test type.
• When writing essay exam answers, you might scan the question for command words such as “compare” or “evaluate” before you start.

Practice and limits

Fast reading is a skill that improves with practice but has limits. Claims that anyone can read at several times normal speed with full comprehension should be treated with caution. As a general pattern, speed and detailed comprehension tend to trade off against each other, so the goal is to choose the right speed for the task, not to be as fast as possible.

Some ways to practice:

• Set a short time limit (a few minutes) to skim an article and then write three sentences on what it said. Check against a careful read.
• Pick a question, such as “When did this event happen?”, and scan a text for the answer, timing yourself.
• Notice when you skim a text that needed careful reading. If you find yourself rereading often, slow down.

For vocabulary, note that skimming will not help you learn new words; careful reading and practice do, as covered in discussions of vocabulary building.

A short decision guide

• Need the main idea or want to decide whether to read? Skim.
• Need a particular fact, name or number? Scan.
• Need to understand, remember or critique? Read carefully, perhaps after skimming first.