Definition of Reliability in Research

Definition of Reliability in Research Reliability is the degree to which a measurement instrument gives the same results each time that it is used, assuming that the underlying thing being measured does not change. Key Takeaways: Reliability If a measurement instrument provides similar results each time it is used (assuming that whatever is being measured stays the same over time), it is said to have high reliability.Good measurement instruments should have both high reliability and high accuracy.Four methods sociologists can use to assess reliability are the test-retest procedure, the alternate forms procedure, the split-halves procedure, and the internal consistency procedure. An Example Imagine that you’re trying to assess the reliability of a thermometer in your home. If the temperature in a room stays the same, a reliable thermometer will always give the same reading. A thermometer that lacks reliability would change even when the temperature does not. Note, however, that the thermometer does not have to be accurate in order to be reliable. It might always register three degrees too high, for example. Its degree of reliability has to do instead with the predictability of its relationship with whatever is being tested. Methods to Assess Reliability In order to assess reliability, the thing being measured must  be measured more than once. For example, if you wanted to measure the length of a sofa to make sure it would fit through a door, you might measure it twice. If you get an identical measurement twice, you can be confident you measured reliably. There are four procedures for assessing the reliability of a test. (Here, the term test refers to a group of statements on a questionnaire, an observers quantitative or qualitative  evaluation, or a combination of the two.) The Test-Retest Procedure Here, the same test is given two or more times. For example, you might create a questionnaire with a set of ten statements to assess confidence. These ten statements are then given to a subject twice at two different times. If the respondent gives similar answers both times, you can assume the questions assessed the subjects answers reliably. One advantage of this method is that only one test needs to be developed for this procedure. However, there are a few downsides of the test-retest procedure. Events might occur between testing times that affect the respondents answers; answers might change over time simply because people change and grow over time; and the subject might adjust to the test the second time around, think more deeply about the questions, and reevaluate their answers. For instance, in the example above, some respondents might have become more confident between the first and second testing session, which would make it more difficult to interpret the results of the test-retest procedure. The Alternate Forms Procedure In the alternate forms procedure (also called parallel forms reliability), two tests are given. For example, you might create two sets of five statements measuring confidence. Subjects would be asked to take each of the five-statement questionnaires. If the person gives similar answers for both tests, you can assume you measured the concept reliably. One advantage is that cueing will be less of a factor because the two tests are different. However, its important to ensure that both alternate versions of the test are indeed measuring the same thing. The Split-Halves Procedure In this procedure, a single test is given once. A grade is assigned to each half separately and grades are compared from each half. For example, you might have one set of ten statements on a questionnaire to assess confidence. Respondents take the test and the questions are then split into two sub-tests of five items each. If the score on the first half mirrors the score on the second half, you can presume that the test measured the concept reliably. On the plus side, history, maturation, and cueing arent at play. However, scores can vary greatly depending on the way in which the test is divided into halves. The Internal Consistency Procedure Here, the same test is administered once, and the score is based upon average similarity of responses. For example, in a ten-statement questionnaire to measure confidence, each response can be seen as a one-statement sub-test. The similarity in responses to each of the ten statements is used to assess reliability. If the respondent doesnt answer all ten statements in a similar way, then one can assume that the test is not reliable. One way that researchers can assess internal consistency is by using statistical software to calculate Cronbach’s alpha. With the internal consistency procedure, history, maturation, and cueing arent a consideration. However, the number of statements in the test can affect the assessment of reliability when assessing it internally.

Semantic Field Definition and Examples

Semantic Field Definition and Examples A semantic field is a set of words (or lexemes) related in meaning. The phrase is also known as a word field, lexical field, field of meaning, and semantic system. Linguist Adrienne Lehrer has defined semantic field more specifically as a set of lexemes which cover a certain conceptual domain and which bear certain specifiable relations to one another (1985). Examples and Observations The subject matter often unites a semantic field. The words in a semantic field share a common semantic property. Most often, fields are defined by subject matter, such as body parts, landforms, diseases, colors, foods, or kinship relations.... Lets consider some examples of semantic fields....The field of stages of life is arranged sequentially, though there is considerable overlap between terms (e.g., child, toddler) as well as some apparent gaps (e.g., there are no simple terms for the different stages of adulthood). Note that a term such as minor or juvenile belongs to a technical register, a term such as kid or tot to a colloquial register, and a term such as sexagenarian or octogenarian to a more formal register. The semantic field of water could be divided into a number of subfields; in addition, there would appear to be a great deal of overlap between terms such as sound/fjord or cove/harbor/bay. (Laurel J. Brinton, The Structure of Modern English: A Linguistic Introduction. John Benjamins, 2000) Metaphors and Semantic Fields Semantic fields are also sometimes called fields of meaning: Cultural attitudes to particular areas of human activity can often be seen in the choices of metaphor used when that activity is discussed. A useful linguistic concept to be aware of here is that of semantic field, sometimes called just field, or field of meaning.... The semantic field of war and battle is one that sports writers often draw on. Sport, particularly football, in our culture is also associated with conflict and violence. (Ronald Carter, Working With Texts: A Core Introduction to Language Analysis. Routledge, 2001) More and Less Marked Members of a Semantic Field Color terms also help illustrate how words are grouped into a semantic field. In a semantic field, not all lexical items necessarily have the same status. Consider the following sets, which together form the semantic field of color terms (of course, there are other terms in the same field): Blue, red, yellow, green, black, purpleIndigo, saffron, royal blue, aquamarine, bisque The colors referred to by the words of set 1 are more usual than those described in set 2. They are said to be less marked members of the semantic field than those of set 2. The less marked members of a semantic field are usually easier to learn and remember than more marked members. Children learn the term blue before they learn the terms indigo,, royal blue, or aquamarine. Often, a less marked word consists of only one morpheme, in contrast to more marked words (contrast blue with royal blue or aquamarine). The less marked member of a semantic field cannot be described by using the name of another member of the same field, whereas more marked members can be thus described (indigo is a kind of blue, but blue is not a kind of indigo). Less marked terms also tend to be used more frequently than more marked terms; for example, blue occurs considerably more frequently in conversation and writing than indigo or aquamarine....Less marked terms are also often broader in meaning than more marked terms.... Finally, less marked words are not the result of the metaphorical usage of the name of another object or concept, whereas more marked words often are; for example, saffron is the color of a spice that lent its name to the color. (Edward Finegan. Language: Its Structure and Use, 5th ed. Thomson Wadsworth, 2008)