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?
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.
Published on
August 8, 2019
by
Fiona Middleton.
Revised on
August 19, 2022.
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.
There are four main types of reliability. Each can be estimated by comparing different sets of results produced by the same method.
Published on
July 3, 2019
by
Fiona Middleton.
Revised on
October 10, 2022.
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.
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.
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.
Published on
June 21, 2019
by
Fiona Middleton.
Revised on
October 10, 2022.
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”).
Published on
May 31, 2019
by
Fiona Middleton.
Revised on
October 10, 2022.
Apostrophes have two main uses:
Indicating possession (e.g., The student’s paper)
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.
Published on
May 23, 2019
by
Fiona Middleton.
Revised on
October 10, 2022.
Commas are used to split up different parts of a sentence, and when used correctly they bring clarity and flow to your writing. They’re probably the most common piece of punctuation in English, which means that they’re often the most misused.
This article takes you through the most important comma rules and the most common mistakes.
Published on
May 15, 2019
by
Fiona Middleton.
Revised on
October 10, 2022.
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 tothe shop.
I’ve been unwell sincelast Wednesday.
That gift is forhim.
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.
Published on
April 30, 2019
by
Fiona Middleton.
Revised on
October 17, 2022.
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 resultis significant.
The resultsare significant.
Do
The studentdoes her best.
The studentsdo their best.
Become
The childbecomes happier.
The childrenbecome happier.
Cause
That treecauses hay fever.
Those treescause hay fever.
Analyze
The authoranalyzes the text.
The authorsanalyze 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.
