science

Lix (readability test)

Lix (readability test) is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lix (readability test) rather than just read about it. In short: LIX (abbreviation of Swedish läsbarhetsindex, "readibility index") is a readability measure indicating the difficulty of reading a text developed by Swedish scholar Carl-Hugo Björnsson. It is defined as a sum of two numbers: the average sentence length and the percentage of words of more than six letters.

Key takeaways

Lix (readability test) belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lix (readability test) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lix (readability test) from memory before moving on to harder problems.

Reference excerpt

LIX (abbreviation of Swedish läsbarhetsindex, "readibility index") is a readability measure indicating the difficulty of reading a text developed by Swedish scholar Carl-Hugo Björnsson. It is defined as a sum of two numbers: the average sentence length and the percentage of words of more than six letters.

LIX = average sentence length + percentage of words of more than six letters {\displaystyle {\text{LIX}}={\text{average sentence length}}+{\text{percentage of words of more than six letters}}}

Scores usually range from 20 ("very easy") to 60 ("very difficult").

The exact formula is:

LIX = A B + C ⋅ 100 A {\displaystyle {\text{LIX}}={\frac {A}{B}}+{\frac {C\cdot 100}{A}}} , where

A {\displaystyle A} is the number of words,

B {\displaystyle B} is the number of periods (defined by period, colon or capital first letter), and

C {\displaystyle C} is the number of long words (more than 6 letters).

References

Further reading Björnsson, C. H. (1968). Läsbarhet. Stockholm: Liber. Björnsson, C. H. (1971). Læsbarhed. København: Gad.

External links Detailed LIX calculator (in Swedish)

Worked examples

Example 1 — a first encounter with Lix (readability test)

Start with the simplest possible case. Write down what Lix (readability test) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lix (readability test) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lix (readability test) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lix (readability test)

In research: Lix (readability test) appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lix (readability test) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lix (readability test) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Readability, so understanding it makes those chapters shorter.
In everyday life: Look for Lix (readability test) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Lix (readability test)” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Lix (readability test) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lix (readability test) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lix (readability test) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lix (readability test) in simple terms?

Why does Lix (readability test) matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lix (readability test)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lix (readability test).