# Percentage of unknown words in courses

What is the algorythm of displaying the percentage of unknown words in courses?
Why all the lessons in the course have from 17% to 26% of unknown words but the course displays only 3007 (14%)?
The more the course the lessons has, the smaller the relative percentage is.

Example:
141 (17%)
195 (21%)
148 (16%)
318 (26%)

146 (20%)

Total 3007 (14%) - how???

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Hi Ress,
Looks like percentage of new words in a course info is wrong. Thanks for letting us know, I’ll report that.

Isn’t it because those words are used in further lessons too? So while there is bigger number of unknown words in a single lesson, in a whole course they are appearing over and over again so overall percentage is not that high. Not sure if I made myself clear but that kinda makes sense to me.

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Of course this is the reason. Imagine you have only one unknown word in the whole course.
If it reappears in many lessons, each time the percentage will be calculated from the lesson’s total words. While in the whole course it will be treated just as one word.

Let’s have a course with 2 lessons, 100 words in each. Let they have 10 and 20 unknown words, so 10% and 20%. Let’s suppose there are 5 the same unknown words in both lessons.
So, it may be (10+20-5):(100+100-5) = 25:195 or about 13%.
But I would like to see 15% for the course (an average between 10% and 20%).

May I propose to calculate the percentages for every lesson in the course and than take the average value of the percentages?

I understand your point, but at least for me the existing method works better. For example if I import a large text or a book, I will clearly see what percentage of the words is unknown to me as a whole. In that case I don’t care much about lessons, because they are created only due to technical limitations of Lingq. I still treat all the lessons as one text/book.

Try to open a course of a language where you 0 words know.
My results: 5 lessons, 100% unknown words in each. But the course has just 79%.
Are you kidding? I know 0 words in this language! How can I get 79%?

It’s not correct to use an arithmetic average for ratios or percentages. It should be a geometric one. Anyway an average of ratios is not the same as a total ratio

This is now fixed. Thanks for reporting the issue.

Hi Zoran, thank you for the update.
But it seems to be not so simple.

It shows 100% for lessons and courses in languages where I have 0 known words. That’s great!

A course has 6 lessons, 1229 (47%)
233 (37%)
332 (40%)
203 (32%)
207 (35%)
201 (41%)
183 (31%)

Another example. I have a course with 2618 (35%) unknown words in 95 lessons.
But the worst percentage is 55 (20%), the smallest is 3 (2%).
Why does it have 35%?

Do you think it’s correct? I mean, it was showing too optimistic values before, but now it seems to be pessimistic.

Yes, should be correct now.
You said that your course has 1229 new words - 47%, the reason why percentage is lower in lessons is because lot of words which are known for you already repeat through all the lessons within a course.
If lessons 1 has 233 new words - 37%
Lessons 2,3,4,5 and 6 has - 40%, 32%, 35%, 41% and 31% , that means that lot of about 60% known words in each lessons repeat, and that is why number of New words is higher in course details.

For courses with more lessons this number can vary even more, as you said one lesson has only 2% of new words, but even those 2 procent will increase the course % of new words.

Sorry if this should be a new thread but in this course: Login - LingQ
It shows the course’s new words as 9069 = 133% for me. That’s odd isn’t it?

One more example.
I have 12737 known words in a language.
A course has 263 Lessons with percentage between 11% and 57% (usually 20%-30%).
The funniest thing is the percentage of the course!
New words:19327 (99%)

Does this really mean my 12737 known words is just 1% percents of the words in the single course?

The same language, 206 Lessons in a course, New words:15017 (86%). But the lessons have 13%-40%.

Another language with 32373 known words.
A course with 95 Lessons with 1%-22% for each lesson.
The couse has 3083 new words (42%)

The same language, I remind, it has 32k of known words.
A course with 36 Lessons. They are really difficult, 17%-34%
But the course has New words:9324 (83%)

OK, the 3rd language, the most funniest one.
I have 16262 known words.
A course with 103 Lessons has New words:11191 (106%)
A course with 92 Lessons has New words:15118 (113%)

Thank you for sharing new Slovak language. Please check the percentage in the new courses there.
I guess we must have the same numbers if you did not start learning Slovak yet.

New words: 1721 (221%)
New words: 2017 (208%)
New words: 1124 (171%)

Hi Ress,
Yes, that is strange. We will look into the percentages again.