Objectives by the end of this chapter students will be able to. Introduction to statistics and levels of measurement. This topic is usually discussed in the context of academic. The four scales of measurement are nominal, ordinal, interval, and ratio. The four scales of measurement specified by stevens were the nominal, ordinal, interval, and ratio scales. This allows measurement of attitudes, beliefs, and perceptions, and provides a means of quantifying the data. Interval and ratio levels of measurement are sometimes called continuous or scale. Scales of measurement nominal, ordinal, interval and ratio. These are simply ways to categorize different types of variables. Measurement of sea level is another example of an interval scale.
It does not take a lot of thought to recognize that likert scales are ordinal. Chapter 7 measurement m easurement is the foundation of scientific inquiry. Level of measurement or scale of measure is a classification that describes the nature of information within the values assigned to variables. In 1946, harvard university psychologist stanley smith stevens developed the theory of the four levels of measurement when he published an article in science entitled, on the theory of scales of measurement. To quote a recent article in medical education jamieson 2004 the. The rankings are ordered from 1 to 50, but there is no way to compare the differences in rankings. Likert scales, levels of measurement and the laws of. Stevenss definition of measurement and the four levels of measurement he described have since become iconic in social science measurement. By knowing the different levels of data measurement, researchers are able to choose the best method for statistical analysis. Variable is a characteristic, number, or quantitythat increases or decreases over time, ortakes different values in differentsituations. Departments making sense of methods and measurement. Nominal, ordinal, interval and ratio csc 238 fall 2014 there are four measurement scales or types of data. You decide to measure depression on the following scale. Measurement and measurement scales measurement is the foundation of any scientific investigation everything we do begins with the measurement of whatever it is we want to study definition.
But there are different levels of measurement, which provide differing amounts of information about the theoretical. Is your dependent variable measured at the highest level. Four types of measurement scales nominal ordinal interval ratio the scales are distinguished on the relationships assumed to exist between objects having different scale values the four scale types are ordered in that all later scales have all the properties of earlier scales plus additional properties. The levels of measurement, or scales of measure are expressions that typically refer to the theory of. Level of measurement from wikipedia, the free encyclopedia the levels of measurement, or scales of measure are expressions that typically refer to the theory of scale types developed by the psychologist stanley smith stevens. Likert scales, levels of measurement and the laws of statistics geoff norman 1 advances in health sciences education volume 15, pages 625 632 2010 cite this article. If a change from 1 to 2 has the same strength as a 4 to 5, then we would call it an interval level measurement if not, then its just an ordinal qualitative measurement. The fahrenheit scale is a clear example of the interval scale of measurement. Levels of measurement lesson transcript edward volchok, phd page 1 of 28 audio this is edward volchok and welcome to our lecture on measurement scales or, as these scales are frequently called, levels of measurement. On the theory of scales of measurement sage research. Statistics and levels of measurement how to figure things out.
It is important for the researcher to understand the different levels of measurement, as these levels of measurement, together with how the research question is phrased, dictate what statistical. Level of measurement overview, types of scales, examples. The distinction between interval and ratio scales is rather subtle. Likerttype scales are assumed to have equal units as the categories move from most negative to most positive. In simple words, we must measure what we have defined. For example, the difference in finishing time between the 1st place horse and the 2nd horse need not the same as that between the 2nd and 3rd place horses. Interval scale offers labels, order, as well as, a specific. The nominal scale is a scale of measurement that is used for identification purposes. Levels of measurement research methods knowledge base. Level of measurement pop quiz identify the following as nominal level, ordinal level, interval level, or ratio level data. Interval scale offers labels, order, as well as, a.
In this famous article, stevens argued that all measurement is conducted using four measurement levels. Stevens proposed his theory in a 1946 science article titled on the theory of scales of measurement. Indeed it is often referred to as a categorical scale. A nominal scale is the lowest level of measurement and is most often used with variables that are qualitative categorical in nature rather than quantitative. Four statistical scales of measurement simplyeducate. Each scale of measurement has certain properties which in turn determines the appropriateness for use of certain statistical analyses. Each level of measurement scale has specific properties that determine the various use of statistical analysis. If a change from 1 to 2 has the same strength as a 4 to 5, then we would call it an interval level measurement if. Levels of measurement and scaling scales 110 chapter 3. Nominal scale is a naming scale, where variables are simply named or labeled, with no specific order. A general and important guideline is that the statistics based on one level of measurement should not be used for a lower level, but can be used for a higher level. In the course of gathering your data, you should be very well familiar with the different statistical scales of measurement. The four measurement levels, in order, from the lowest level of information to the highest level of information are as follows. Levels of measurement and choosing the correct statistical.
In this article, we will learn four types of scales such as nominal, ordinal, interval and ratio scale. Research methods levels of measurement nominal, ordinal. Four levels of measurement and the statistics appropriate. Each level of measurement and its corresponding scale is able to measure one or more of the four properties of. Measurement is defined in terms of the relationship to related factors and brief illustration of variables and types. That is, they can be measured only in terms of whether the individual items belong to some distinctively different categories, but we cannot. Pdf levels of measurement describe the relationship between the. The following article enumerates and describes the four statistical scales of measurement and provides examples with exercises. Pdf likert scales, levels of measurement adn the laws.
With each of these scales there is direct, measurable quantity with equality of units. Psychologist stanley smith is known for developing four levels of measurement. In statistics, the variables or numbers are defined and categorized using different scales of measurements. Nominal scales contain the least amount of information. This classification of levels of measurement was first proposed by s. State the question that statistics is always trying to answer. These were developed by psychologist stanley smith stevens, who wrote about them in a 1946 article in science, titled on the theory of scales of measurement. Thus, 60 degree fahrenheit or 10 degrees fahrenheit are interval data. These scales may have their basis in nominal, ordinal, interval, or ratio types of data. Likert scale examples for surveys iowa state university.
Likert scales, levels of measurement adn the laws of statistics article pdf available in advances in health sciences education 155. Psychologist stanley smith stevens developed the bestknown classification with four levels, or scales, of measurement. Levels of measurement and choosing the correct statistical test. We use different ingredients for different recipes. It is a system of classification and does not place the entity along a continuum. Choice of the statistical analyses in the social sciences typically. A variable has one of four different levels of measurement. This knowledge will help you adequately and appropriately measure the variables that you have. Each level of measurement and its corresponding scale is able to measure one. The four levels of measurement scales for measuring variables with their definitions, examples and questions. Scales of measurement refer to ways in which variablesnumbers are defined and categorized.
This framework of distinguishing levels of measurement originated. Most textbooks distinguish among nominal, ordinal, interval, and ratio scales based on a classification system developed by stevens 1946. Levels of scale measurement the four levels or types of scale measurement are nominal, ordinal, interval, and ratio level scales. Part 7 of this volume includes scales that measure a wide variety of social and behavioral variables. Not for sale or distribution statistics and levels not. Within science, there are four commonly used levels and scales of measurement. Although likerttype scales are very common when a survey instruments are used to. But note that in interval measurement ratios dont make any sense 80 degrees is not twice as hot as 40 degrees although the attribute value is twice as large.
Levels of measurement for quantitative research susan prion, edd, rn, cnea, katie anne adamson, phd, rnb aschool of nursing and health professions, university of san francisco, san francisco, ca 941171080, usa buniversity of washington tacoma, tacoma, wa 98402, usa the purpose of research is to. In order to test our hypotheses, we must observe our theoretical concepts at the operational level. Fahrenheit temperature scales are examples of interval measurements. The zero for the fahrenheit and celsius scales is not the same, as we can have negative temperatures with these scales. Ordinal scale has all its variables in a specific order, beyond just naming them. Nominal variables allow for only qualitative classification. Michell, in fact, described the controversy over scales of measurement as a clash of.
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