An error checking test asks you to compare two pieces of information and spot where they differ. It is a speed and accuracy task, not a reasoning puzzle.
You are shown a source and a copy of the same data, such as two tables or two strings of codes, and you must find the mismatches. Publishers vary in layout and timing, but the skill is always careful, systematic comparison under mild time pressure.
Imagine a clerk typing customer records from a paper form into a system. A checker then places the form beside the screen and looks for slips. Error checking tests turn that job into a short exercise. Two items appear together, and exactly one of them is treated as correct.
The differences are usually small and ordinary: two digits swapped, a letter changed, a missing character, a decimal point in the wrong place, or a row that has moved. Nothing is hidden behind wordplay. What makes it hard is that your eye wants to see what it expects, so a mistake that looks "almost right" can slide past.
Because the content is so plain, the test is often used for roles built around processing information, such as administration, data entry, finance operations and customer support. Whether a particular employer uses one is something only that employer can tell you.
Not every provider uses every layout, and some timed versions show the pairs one at a time. The principle below applies to all of them.
Below is a source table, followed by the copy that a colleague typed. The question: how many rows of the copy contain at least one error?
| Order | Customer | Postcode | Amount (EUR) |
|---|---|---|---|
| 4471 | A. Brandt | N7 4QX | 1,250.00 |
| 5832 | M. Osei | LS2 9JT | 310.50 |
| 6015 | K. Lindqvist | B15 2TT | 2,075.00 |
| 6290 | P. Novak | M4 1HN | 98.40 |
| 7144 | S. Rahman | E8 3DL | 640.00 |
| 7203 | T. Alvarez | G12 8QQ | 1,180.25 |
| Order | Customer | Postcode | Amount (EUR) |
|---|---|---|---|
| 4471 | A. Brandt | N7 4QX | 1,250.00 |
| 5832 | M. Osei | LS2 9JT | 301.50 |
| 6015 | K. Lindquist | B15 2TT | 2,075.00 |
| 6290 | P. Novak | M4 1HN | 98.40 |
| 7144 | S. Rahman | E8 3LD | 640.00 |
| 7230 | T. Alvarez | G12 8QQ | 1,180.52 |
ReasonEra is a browser-based AI tutor for practising aptitude question types. For error checking, take a screenshot of a practice item from a test you are preparing for, upload it, and choose "Quick Verify" to see the answer or "Tutor Explanation" to see which cells differ and why. Reading the explanation matters more than the verdict, because it shows you where your eye skipped.
Start with the free error checking practice test: ten original timed questions, scored and explained. A free account includes 3 trials, and the 14-Day Pass is 49 € for unlimited use for 14 days.
Use ReasonEra to build the skill, but the rules of a graded test come from the employer, not from us, so check the instructions before you rely on any tool.
It is not conceptually hard, but it is demanding because it combines speed with accuracy. Most people improve noticeably with a few timed practice sessions.
It is used to look at attention to detail when handling data, so it appears in some processes for administrative, clerical and data-focused roles. Which employers use it varies.
That depends on the scoring rules of the specific test. Read the instructions first, because some schemes penalise wrong answers and others do not.
Use one fixed comparison order, practise with timed sets and review every miss to see which kind of slip you overlooked. Speed usually follows accuracy.
You can upload a screenshot of an error checking practice question and get an explained answer, and there is a free error checking practice test on the site. Use it for practice and learning.
First learn why an answer is right, then practise getting there faster. Start with the free trials.
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Notes. The advice here reflects common practice across providers, so your own invitation takes priority. Notice an error? Tell us at info@reasonera.com.