computer science

User error

User error is a computer 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 User error rather than just read about it. In short: A user error is an error made by the human user of a complex system, usually a computer system, in interacting with it. Although the term is sometimes used by human–computer interaction practitioners, the more formal term human error is used in the context of human reliability.

Key takeaways

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

Reference excerpt

A user error is an error made by the human user of a complex system, usually a computer system, in interacting with it. Although the term is sometimes used by human–computer interaction practitioners, the more formal term human error is used in the context of human reliability. Related terms such as PEBKAC ("problem exists between keyboard and chair"), PEBMAC ("problem exists between monitor and chair"), identity error or ID-10T/1D-10T error ("idiot error"), PICNIC ("problem in chair, not in computer"), IBM error ("idiot behind machine error"), skill issue ("lack of skill"), and other similar phrases are also used as slang in technical circles with derogatory meaning. This usage implies a lack of computer savviness, asserting that problems arising when using a device are the fault of the user. Critics of the term argue that many problems are caused instead by poor product designs that fail to anticipate the capabilities and needs of the user. The term can also be used for non-computer-related mistakes.

Causes Joel Spolsky points out that users usually do not pay full attention to the computer system while using it. He suggests compensating for this when building usable systems, thus allowing a higher percentage of users to complete tasks without errors:

For example, suppose the goal of your program is to allow people to convert digital camera photos into a web photo album. If you sit down a group of average users with your program and ask them all to complete this task, then the more usable your program is, the higher the percentage of users that will be able to successfully create a web photo album. To be scientific about it, imagine 100 real world users. They are not necessarily familiar with computers. They have many diverse talents, but some of them distinctly do not have talents in the computer area. Some of them are being distracted while they try to use your program. The phone is ringing. The baby is crying. And the cat keeps jumping on the desk and batting around the mouse. Now, even without going through with this experiment, I can state with some confidence that some of the users will simply fail to complete the task, or will take an extraordinary amount of time doing it.

Experts in interaction design such as Alan Cooper believe this concept puts blame in the wrong place, the user, instead of blaming the error-inducing design and its failure to take into account human limitations. Bruce "Tog" Tognazzini describes an anecdote of Dilbert creator Scott Adams losing a significant amount of work of comment moderation at his blog due to a poorly constructed application that conveyed a wrong mental model, even though the user took explicit care to preserve the data. Jef Raskin advocated designing devices in ways that prevent erroneous actions. Don Norman suggests changing the common technical attitude towards user error:

Don't think of the user as making errors; think of the actions as approximations of what is desired.

Acronyms and other names Terms like PEBMAC/PEBCAK or an ID10T error are often used by tech support operators and computer experts to describe a user error as a problem that is attributed to the user's ignorance instead of a software or hardware malfunction. These phrases are used as a humorous way to describe user errors. A highly popularized example of this is a user mistaking their CD-ROM tray for a cup holder, or a user looking for the "any key". However, any variety of stupidity or ignorance-induced problems can be described as user errors.

PEBKAC/POBCAK/PICNIC Phrases used by the tech savvy to mean that a problem is caused entirely by the fault of the user include PEBKAC (an acronym for "problem exists between keyboard and chair"), PEBCAK (an alternative, but similar, acronym for "problem exists between chair and keyboard"), POBCAK (a US government/military acronym for "problem occurs between chair and keyboard"), PICNIC ("problem in chair not in computer"), "cockpit error", and EBKAC ("Error between keyboard and chair"). Another variant is PEBUAK (Problem Exists Between User and Keyboard). In 2006, Intel began running a number of PEBCAK web-based advertisements to promote its vPro platform. If the same sentiment wants to be conveyed without using an acronym, the phrase "chair to keyboard interface error" is often used.

ID-10-T error ID-Ten-T error (also seen as ID10T and ID107) is a masked jab at the user: when ID-Ten-T is spelled out it becomes ID10T ("IDIOT"). It is also known as a "Ten-T error" or "ID:10T error". The User Friendly comic strip presented this usage in a cartoon on 11 February 1999. In United States Navy and Army slang, the term has a similar meaning, though it is pronounced differently:

The Navy pronounces ID10T as "eye dee ten tango". The Army instead uses the word 1D10T which it pronounces as "one delta ten tango".

In other languages

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with User error

Start with the simplest possible case. Write down what User error claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer 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 User error 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 User error 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 User error

In research: User error appears in computer 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 User error 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: User error is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer humour, Computer jargon, In-jokes, so understanding it makes those chapters shorter.
In everyday life: Look for User error 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.

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How to study User error in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what User error 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 User error out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is User error in simple terms?

Why does User error matter?

Because it connects several computer 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 User error?

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 User error.