The 4 Types of Validity in Research | Definitions & Examples

Validity tells you how accurately a method measures something. If a method measures what it claims to measure, and the results closely correspond to real-world values, then it can be considered valid. There are four main types of validity:

  • Construct validity: Does the test measure the concept that it’s intended to measure?
  • Content validity: Is the test fully representative of what it aims to measure?
  • Face validity: Does the content of the test appear to be suitable to its aims?
  • Criterion validity: Do the results accurately measure the concrete outcome they are designed to measure?

In quantitative research, you have to consider the reliability and validity of your methods and measurements.

Note that this article deals with types of test validity, which determine the accuracy of the actual components of a measure. If you are doing experimental research, you also need to consider internal and external validity, which deal with the experimental design and the generalizability of results.

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The 4 Types of Reliability in Research | Definitions & Examples

Reliability tells you how consistently a method measures something. When you apply the same method to the same sample under the same conditions, you should get the same results. If not, the method of measurement may be unreliable or bias may have crept into your research.

There are four main types of reliability. Each can be estimated by comparing different sets of results produced by the same method.

Type of reliability Measures the consistency of…
Test-retest The same test over time.
Interrater The same test conducted by different people.
Parallel forms Different versions of a test which are designed to be equivalent.
Internal consistency The individual items of a test.

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Reliability vs. Validity in Research | Difference, Types and Examples

Reliability and validity are concepts used to evaluate the quality of research. They indicate how well a method, technique. or test measures something. Reliability is about the consistency of a measure, and validity is about the accuracy of a measure.opt

It’s important to consider reliability and validity when you are creating your research design, planning your methods, and writing up your results, especially in quantitative research. Failing to do so can lead to several types of research bias and seriously affect your work.

Reliability vs validity
Reliability Validity
What does it tell you? The extent to which the results can be reproduced when the research is repeated under the same conditions. The extent to which the results really measure what they are supposed to measure.
How is it assessed? By checking the consistency of results across time, across different observers, and across parts of the test itself. By checking how well the results correspond to established theories and other measures of the same concept.
How do they relate? A reliable measurement is not always valid: the results might be reproducible, but they’re not necessarily correct. A valid measurement is generally reliable: if a test produces accurate results, they should be reproducible.

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How to Tell If a Noun Is Countable or Uncountable | Examples

Uncountable nouns, also known as mass nouns or noncount nouns, refer to a mass of something or an abstract concept that can’t be counted (except with a unit of measurement). In contrast, countable nouns can be counted as individual items.

The main rules to remember for uncountable nouns are that they cannot be pluralized, and that they never take indefinite articles (“a” or “an”).

Common examples of uncountable nouns
Type of noun Examples
Abstract concepts and physical phenomena research, advice, information, knowledge, money, logic, gravity, acceleration, pollution, feedback, traffic, radiation, biomass, lightning
Substances, materials and foods air, water, blood, algae, mud, grass, seaweed, graphite, clay, quartz, rice, flour, meat
Elements, chemicals and gases helium, iron, copper, hydrochloric acid, calcium carbonate, carbon monoxide, methane
Disciplines and fields biology, chemistry, physics, mathematics, geography, psychology, economics, aquaculture, trigonometry

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Apostrophes | Definition, Guide, Rules & Examples

Apostrophes have two main uses:

  1. Indicating possession (e.g., The student’s paper)
  2. Indicating a contraction (e.g., She’s writing a paper)

    Contractions should be avoided in academic writing, but possessive apostrophes are used in all types of writing. Make sure to use them correctly, especially when dealing with plurals and abbreviations.

    Use a possessive apostrophe…
    This study examines the company’s efforts to expand.
    I highly recommend Sharon’s salon.
    My parents’ support was essential.
    The crowd’s applause could be heard for miles.
    In the last quarter, BP’s profits dropped.
    Don’t use an apostrophe…
    The results are surprising.
    Remember what happened three Christmases ago?
    Several NGOs were present at the conference.
    We can identify the following KPIs.
    The 1920s was a golden age for art.
    During the 2010s politics slid into confusion.
    The cobra reared its head.
    Whose snake is that?

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    What Are Prepositions? | List, Examples & How to Use

    Prepositions are words that show the relationship between elements in a sentence. They can express relationships of place, time, direction, and other abstract or logical connections.

    A preposition is usually located directly before the word or phrase that it relates to – the object of the preposition.

    • We walked to the shop.
    • I’ve been unwell since last Wednesday.
    • That gift is for him.

    Prepositions are flexible words that are often central to the meaning of a sentence, and it can be tricky to choose the right one. The best way to master them is by reading and practice.

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    Subject-Verb Agreement | Examples, Rules & Use

    Subject-verb agreement means that the subject of the sentence matches the verb describing its action. This helps your reader understand who or what is doing something and makes your writing easier to read.

    First, identify the subject (the person or thing doing the action) and the verb (the action word) in a sentence. If the subject is singular, the verb describing its action should be singular. If the subject is plural, the verb should be plural.

    Verb Singular subject + verb Plural subject + verb
    Be The result is significant. The results are significant.
    Do The student does her best. The students do their best.
    Become The child becomes happier. The children become happier.
    Cause That tree causes hay fever. Those trees cause hay fever.
    Analyze The author analyzes the text. The authors analyze the text.

    While subject-verb agreement is easy in simple sentences like these, it can become tricky in more complex sentences. This article teaches you the most important rules and common mistakes.

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