science

Informal methods of validation and verification

Informal methods of validation and verification 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 Informal methods of validation and verification rather than just read about it. In short: Informal methods of validation and verification are some of the more frequently used in modeling and simulation. They are called informal because they are more qualitative than quantitative.

Key takeaways

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

Reference excerpt

Informal methods of validation and verification are some of the more frequently used in modeling and simulation. They are called informal because they are more qualitative than quantitative. While many methods of validation or verification rely on numerical results, informal methods tend to rely on the opinions of experts to draw a conclusion. While numerical results are not the primary focus, this does not mean that the numerical results are completely ignored. There are several reasons why an informal method might be chosen. In some cases, informal methods offer the convenience of quick testing to see if a model can be validated. In other instances, informal methods are simply the best available option. Informal methods are not less effective than formal methods and should be performed with the same discipline and structure that one would expect in "formal" methods. When executed properly, solid conclusions can be made. In modeling and simulation, verification techniques are used to analyze the state of the model. Verification is completed by different methods with the focus of comparing different aspects of the executable model with the conceptual model. On the other hand, validation methods are the methods by which a model, either conceptual or executable is compared with the situation it is trying to model. Both are methods by which the model can be analyzed to help find defects in the modeling methods being used, or potential misrepresentations of the real-life situation.

Inspection Inspection is a verification method that is used to compare how correctly the conceptual model matches the executable model. Teams of experts, developers, and testers will thoroughly scan the content (algorithms, programming code, documents, equations) in the original conceptual model and compare with the appropriate counterpart to verify how closely the executable model matches. One of the main purposes of this method of verification is to see what original goals have been overlooked. By doing an inspection check on the model, the team can not only see what issues might have been overlooked, but also catch any potential flaws that can become an issue later in the project. Depending on the resources available, the members of the inspection team may or may not be part of the model production team. Preferably they would be separate groups, but when members are from the same group aspects may be overlooked since the group members have already spent time looking at the project from a production point of view. Inspections are also more flexible in that they may be ad hoc or highly structured, with members of an inspection team assigned specific roles such as moderator, reader, and recorder, and specific procedure steps used in the inspection. The inspectors' goal is to find and document flaws between the conceptual model and the executable model.

Face validation

One of the benefits of face validation is that it can effectively be used during a real-time virtual simulation where the interaction between the user and the simulation is of priority. It is effective during these types of simulations because these types of models require input or interaction from the user. The best way to validate that the model meets the criteria is by having users who have experienced the model situation in real life confirm that the model accurately represents the situation they are familiar with. Users who are familiar with the situation will notice necessary corrections that a developer may be unaware of. This type of validation is effective and most appropriate for virtual simulations and it is also used to validate models when there is a short timeframe scheduled for testing, or when it is difficult to produce quantitative results that can be analyzed. While quantitative results should be the preferred result, a solid account of validation from professionals is also acceptable.

Examples of face validation The accuracy of a flight simulator's response to control inputs can be evaluated by having an experienced pilot fly the simulator through a range of maneuvers. Analyzing the accuracy of a poker bot simulator's response to user input to verify that the A.I. is reacting in a logical manner. Having a soldier test a model that simulates a battle situation.

Audit An audit is used to establish how well a model matches the guidelines that are set in place. If an audit trail is in place, any error in the model should be able to be traced back to the original source to easily find and make corrections. An audit is conducted by meetings and following the audit trail to check for issues.

Examples of audit The most common application of an audit can be seen when a citizen is "audited". While this does not have any direct application to the modeling and simulation methods discussed, it explains the process.

Walkthrough

A walkthrough is a scheduled meeting with the author in charge of the model or documents that are set to be reviewed. In addition to the authors, there is usually a group of senior technical staff and possibly business staff that help analyze the model. Typically, there is also a facilitator who is in charge of leading the meeting. Prior to the official meeting the author will review the document or model for any potential cosmetic errors. After this review it is passed on to the meeting audience so they may thoroughly review it for inconsistencies prior to the meeting. The audience will gather any questions or concerns based on their expertise in the field as well as their knowledge of the system. At the meeting, the author will present the document to the audience and explain the methods and findings. The facilitator is responsible for presenting questions from the audience at this time. In addition to leading the structure of the meeting, the facilitator takes notes of remaining issues to be reanalyzed later.

Examples of walkthrough Authors of a written work sitting down to review the content prior to submitting for publishing. A software development team reviewing a product before the final product is sent for approval by the customer.

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Worked examples

Example 1 — a first encounter with Informal methods of validation and verification

Start with the simplest possible case. Write down what Informal methods of validation and verification 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 Informal methods of validation and verification 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 Informal methods of validation and verification 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 Informal methods of validation and verification

In research: Informal methods of validation and verification 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 Informal methods of validation and verification 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: Informal methods of validation and verification is common in secondary-school and first-year university syllabi. It links to neighbouring topics Quality management, so understanding it makes those chapters shorter.
In everyday life: Look for Informal methods of validation and verification 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 Informal methods of validation and verification in 20 minutes

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

Frequently asked questions

What is Informal methods of validation and verification in simple terms?

Informal methods of validation and verification are some of the more frequently used in modeling and simulation. They are called informal because they are more qualitative than quantitative.

Why does Informal methods of validation and verification 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 Informal methods of validation and verification?

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 Informal methods of validation and verification.