How Accurate Are The Khan Academy Practice Tests?

Khan Academy has 8 SAT practice tests available at the time of this post. But are they accurate?

Here's the story.

When the current form of the SAT was first introduced in 2015, Khan Academy entered into a partnership with The College Board, the makers of the SAT, with the mission of providing more affordable test prep to everyone.

Before the first administration of the test on March 5th, 2016, The College Board released Practice Tests 1 through 4 on Khan Academy so that the first test takers would have some idea of what to expect.

At that time, those 4 practice tests were the only real source of guidance. No one had taken the real exam yet.

Since then, The College Board has released Practice Tests 5-8 on Khan Academy.

Because the Khan Academy tests are actually released by The College Board, they are generally regarded as official and accurate material.

But here's the problem.

Based on our analysis, Practice Tests 1-4 aren't completely accurate.

Whereas Practice Tests 5-8 were past exams administered to students on actual test dates, Practice Tests 1-4 were never administered to students and were simply created as test prep material for test-takers in 2016. They were devised well before new testing had even started.

Why is that important? Because creating a standardized test is not easy—student data is necessary for fine-tuning and curving each exam. It's a constant process of revising the questions and adjusting the overall difficulty.

Since Practice Tests 1-4 were created without the necessary student data, they do not reflect the changes The College Board later made to the exam.

These changes can only be seen in Practice Tests 5-8, which are past exams that were administered only after The College Board had obtained the necessary data.

Here are some of the subtle differences we noticed:


Practice Tests 1-4Actual Tests
1. Inequality questions show up only on the calculator section. Inequality questions show up on both the non-calculator and calculator sections.
2. Circle questions show up only on the calculator section. Circle questions show up on both the non-calculator and calculator sections.
3. Total of 2-3 systems of equations on each test (0-1 on the calculator section) Total of 3-6 systems of equations questions on each test (2-3 on the calculator section)
4. Systems of equations questions are easier to game. For example, the answer choices are ordered pairs like (2, 3) so you can just plug back in and check. There are almost no systems of equations that involve a quadratic. Systems of equations questions are harder since they'll ask for stuff like "What is the value of \(x + y\)?" instead of giving you the ordered pairs to choose from. There are more systems of equations that involve a quadratic: \[\begin{aligned} x^2 + y &= 7 \\ x - y &= 5 \end{aligned}\]
5. No questions involving boxplots A boxplot question appeared on the March 2018 exam. Make sure you know how to interpret a boxplot.
6. There is sometimes a two-part question dealing with scatterplots. There is always a two-part question dealing with scatterplots.
Proportion questions appear more frequently. Here's what I mean by proportion question:
A rectangle was altered by increasing its length by 10 percent and decreasing its width by \(p\) percent. If these alterations decreased the area of the rectangle by 12 percent, what is the value of \(p\) ?
Proportion questions appear much less frequently (almost never). This is a good thing since students often struggle with them.


Practice Tests 1-4Actual Tests
No singular-plural inconsistency questions. Here's an example:
As a pioneer of artificial intelligence in an increasingly digital world, tech giants such as Google and Apple must consider the social impact of their innovations.
Singular-plural inconsistency questions appear more often than not (at least 1).
2. No questions on question marks. Questions on question marks appear occasionally.
No faulty comparison questions. Here's an example:
Books written by 18th century authors are harder to comprehend than 19th century authors.
Faulty comparison questions appear occasionally.
4. Questions testing you on verb tense are simple. The answer is almost always a verb in past tense (e.g. lived) or present tense (e.g. lives). The answer to a verb tense question will occasionally be the present perfect (e.g. has lived) or the past perfect (e.g. had lived).
5. No questions on word pairs. Questions on word pairs appear occasionally (e.g. not only...but also, between...and...,
6. The occasional question on where to place a paragraph. No questions on where to place a paragraph.
7. Overall, questions are more straightforward and not as tricky. Trickier questions will trap you unless you're thorough and read the entire sentence/paragraph. The transition questions and data interpretation questions require greater comprehension of the main argument or the surrounding context.


It's hard to compare the reading sections of different tests because there isn't a good way to quantify the difficulty of each passage and the question types don't fall so neatly into categories.

However, we can pretty much assume the reading section has been refined since Practice Tests 1-4. After all, it's very unlikely The College Board would make adjustments to both the math and writing sections without also making a few changes to the reading section.

My experience indicates that the reading section has in fact been tweaked and is now more difficult. Compared to Practice Tests 1-4, the actual exams have 1-2 passages that are harder to comprehend and some of the questions are trickier.

I hope to provide a more detailed breakdown of the reading section in a future update to this post.

My Advice

The fact that The College Board has never explicitly acknowledged these differences is a huge disservice not only to students but also to the organization they partnered with—Khan Academy.

Though Practice Tests 1-4 do not fully reflect the current state of the exam, I still highly recommend that you use them as practice material 1) because the vast majority of the questions are accurate and 2) because you should never not do a practice test from The College Board.

Practice is always a good thing. Just remember to take your scores on Practice Tests 1-4 with a grain of salt.