The data scale is important in the determination of. Developed in 1932 by rensis likert1 to measure attitudes, the typical likert scale is a 5 or 7point ordinal scale used by respondents to rate the degree to which they agree or disagree with a statement table. Strictly speaking, the likert scale is an ordinal scale and cannot perform arithmetic operations. If the data are interval, then parametric statistics can be used. An ordinal scale of measurement represents an ordered series of relationships or rank order. Analyzing data measured by individual likerttype items. For example, a likert scale that contains five values strongly agree, agree, neither agree nor disagree, disagree, and strongly disagree is ordinal. A typical likert scale item has 5 to 11 points that indicate the degree of agreement with a statement, such as 1strongly agree to 5strongly disagree. Although they represent a scale of sorts when coded, they are not a likert summated scale.
I consistently use nonnumeric symbols or labels, e. An ordinal scale is a measurement scale that allocates values to variables based on their relative ranking with. Analyzing likert data the journal of extension joe. The likert scale analysis using parametric based structural equation modeling sem zainudin awang 1, asyraf afthanorhan2, mustafa mamat3 1,2,3 faculty of economics and management sciences,universiti sultan zainal abidin kampus gong badak, 20 kuala terengganu, malaysia. We cant say for certain if the difference in satisfaction between a 4 and a 5 is the same as that between a 3 and a 4 on a rating scale. The ubiquitous likert item the question above, taken from the 2007 british social attitudes survey, is an example of a likert item. Meanwhile, deny 2007 mentions that likert scale can be analyzed parametrically. How to analyze your likert scale data in spss youtube. Structural equation modeling on likert scale data with. While almost everyone agrees that the likert rating scale provides ordinal data, the argument over whether it also provides interval data rages on. An interval scale is a type of ordinal scale whereby each response is an interval on its own. Some teams may be separated by 1 win whereas others may have a 10 game gap. Is a likert scale considered interval, ratio, or nominal.
Measures in terms of such values as more or less, larger or smaller, but without specifying the size of the intervals. Reduction of data from interval to ordinal level reaction time rank intimacy rating rank 0. Here is a typical footnote inserted in research using interval techniques with likert scales. The four levels of measurement scales for measuring variables with their definitions, examples and questions. Likert scales, levels of measurement and the laws of. It is the most widely used approach to scaling responses in survey research, such that the term or more accurately the likerttype scale is often used interchangeably with rating scale, although there are. In some cases, the measurement scale for data is ordinal, but the variable is treated as continuous. Use and misuse of the likert item responses and other ordinal core.
Joreskog 1994 states that ordinal data describes multilevel category like likert scale. The simple answer is that likert scales are always ordinal. On likert scales, ordinal data and mean values achilleas. There is a longstanding question as to whether likert scales produce ordinal or interval data.
However, these numbered measures are generally considered ordinal and violate some statistical assumptions needed to evaluate them as normally distributed, parametric data. Carifio and perla 5, 6 are among the strongest supporters for treating likerttype responses as interval data, going so far as to suggest that the likertresponses approximate ratio data. When using likert scales, the researcher must consider issues such as categories of response values in the scale, size of the scale, direction of the scale, the ordinal nature of likertderived data, and appropriate statistical analysis of such data. Most researchers would not use a 3point likerttype scale with a statistical technique requiring interval data. Likert invented the likert scale in the 1930s and it is still one of the most used methods in social, psychological, and humanfactors research. Ordinal x x interval x x x ratio x x x x you will notice in the above table that only the ratio scale meets the criteria for all four properties of scales of measurement. Introduction the likert scale is commonly used in survey research especially from social science, management. Likert scales are widely used in social and educational research. Generation of an interval metric scale to measure attitude. Likert, likerttype, and ordinalscale responses are very popular psychometric item scoring schemes for attempting to quantify peoples opinions, interests, or perceived efficacy of an intervention and are used extensively in physical education and exercise science research. Your choice of statistical methods parametric or nonparametric will depend on whether you consider the scale to be ordinal or interval.
Developed in 1932 by rensis likert 1 to measure attitudes, the typical likert scale is a 5 or 7point ordinal scale used by respondents to rate the degree to which they agree or disagree with a statement table. The actual number of categories is not an important issue. Likert items, likert scale, ordinal interval dilemma, cronbachs alpha, ordinal alpha. Likert scale, structural equation modeling sem, ordinal, interval, parametric 1. This article talks about the characteristics of the interval scale with examples and how to create questions using various methods. Ordinal scale has all its variables in a specific order, beyond just naming them. Likert and likert type scale the construction of likert or likert type scale is rooted into the aim of the research sometimes the purpose of the research is to understand about the opinionsperceptions of participants related with single latent variable phenomenon of interest. The likert scale was named after its developer, rensis likert.
Likert items and scales rob johns university of strathclyde 1. There is often a level of indecision, especially on the part of those new to research, whether to use parametric or nonparametric tests especially in the light of the discordant views outlined in the literature regarding the use of these. Is it interval quantitative or ordinal qualitative scale. A very common question is whether it is legitimate to use likert scale data in parametric statistical procedures that require interval data, such as linear regression, anova, and factor analysis.
Interval scale offers labels, order, as well as, a specific. Pdf likert scale is applied as one of the most fundamental and frequently used psychometric tools in. Likert scale items are created by calculating a composite score sum or mean from four or more type. Likerttype scales such as on a scale of 1 to 10, with one being no pain and ten being high pain, how much pain are you in today. Additionally, concerning midpoints issue, methodologically there is not any difference either using or not using midpoints in likert type measurement. Use and misuse of the likert item responses and other. When multiple likert question responses are summed together interval data. Despite the wider use of likert type data, it has limitations as well. Do research participants give interval or ordinal answers. The analyses of likerttype and likert scale data require unique data analysis. A psychometric response scale primarily used in questionnaires to obtain participants preferences or degree of agreement with a statement or set of statements. Interval and ratio data are sometimes referred to as parametric and nominal and ordinal data are referred to as nonparametric.
Likert scale data, on the other hand, are analyzed at the interval measurement scale. Interval scale measures in terms of equal intervals or degrees of difference but without a true zero point. For example, the difference between 60 and 50 degrees is a measurable 10 degrees, as is the. The purpose of a likert scale is to identify the attitude of people towards the given stimulus objects by asking them. Naturally, a scale has to be developed and likert scale is one of the widely used scaling methods for this purpose. Both data types allow the need to classify and express information. Editorial analyzing and interpreting data from likerttype. The legitimacy of assuming an interval scale for likerttype categories is an important issue, because the appropriate descriptive and inferential statistics differ for ordinal and interval variables1,5 and if the wrong statistical technique is used, the researcher increases the chance of coming to the wrong conclusion about the. In relation to ordinalinterval nature of data, likert items generate the ordinal scale data and that of likert scale generates interval scale. Abstract the likert scale is commonly used in survey research using primary and secondary data to measure the respondent. They do make the important distinction between likert scales compared to the answers to individual questions using likerttype responses.
Like in this example, each response in a 5point likert scale is assigned to a numeric value from 15. The classic example of an interval scale is celsius temperature because the difference between each value is the same. Analyzing and interpreting data from likerttype scales. Under what conditions should likert scales be used as. The data are from likert scales, which are ordinal, so parametric statistics cannot be used. While this defeats the original purpose of the likert scale approximating an interval scale it has the advantage of being easy to comprehend by management. You can begin with analyzing and transforming your data from ordinal scale to numeric scale using mean command. In the hierarchy of measurement levels, the ordinal scale is usually considered the second lowest classification order, falling between the nominal and interval scales. Ordinal scale measures in terms of such values as more or less, larger or smaller, but without specifying the size of the intervals. Both ordinal data and interval data are also a unit of measurement for data quantities. You can see this firsthand on this researchgate forum, where us survey geeks and other researchers have been arguing over it since 2014. Using likert type data in social science research semantic scholar. Consider a concept that is physical in nature, say weight. In my opinion, the likert scale is an ordinal scale, because with this scale we cant measure the distance of two levels of scale.
On one hand the difference between values 4 and 6 is the same as the difference between 8 and 10, but on the other hand is it really. Likerts monograph 1932 makes it clear he never intended for the fivepoint, sevenpoint or other response alternatives to be the scale. That said, the distinction between ordinal and interval is based on the specific demands of the analysis being performed. In an ordinal scale, responses can be rated or ranked, but. Nominal scale is a naming scale, where variables are simply named or labeled, with no specific order. Rather, this is an ordinal or arguably interval scale. Pdf the likert scale is widely used in social work research, and is commonly constructed. By depicting the data on a scale, both types of data point out to a. If we can establish equal distances between ordinal numbers they become interval. When several likert items are combined into a scale, so that there are many possible numeric outcomes, the results are often treated as intervalratio data. It is typically a five response category scale ranging from strongly disagree to strongly agree. Measurement quantitative and qualitative differences scale.
The study concluded that in calculating reliability of likert type measurement cronbachs alpha is better to use for interval nature of likert data and ordinal alpha for ordinal nature. The intervals between positions on the scale are monotonic but never so welldefined as to be numerically uniform increments. It is usually treated as an interval scale, but strictly speaking it is an ordinal scale, where arithmetic operations cannot be conducted. However, epistemologically it is better to use midpoints defining its meaning. In this paper, i dissect these arguments, and show that many studies, dating back to. Pdf can likert scales be treated as interval scales. It is up to individual researcher to choose the number of categories according to his or her preference and expert knowledge, for example, gordon et al. Individual responses are normally treated as ordinal data because although the.
Should you care if your rating scale data is interval or. In an ordinal scale, responses can be rated or ranked, but the distance between responses is not measurable. The interval scale is defined as the 3rd quantitative level of measurement where the difference between 2 variables is meaningful. Let us see how it can be considered as an interval scale. The likert scale originated with rensis likert 21, and has a long history of use in kinesiology research, 14, 24. This is not entirely permissible from a theoretical point of view since likert scales are made up of likert items, and so have the same properties. To distinguish individual items from the summated likert scale, we will refer to the individual items as likert. A scale that represents quantity and has equal units but for which zero. This video explains about the analysis steps in spss.
I think, most of the time, these surveys are just ordering responses lowest to highest and not fulfilling the interval scale requirements. Some researchers assume that likert scale data is interval data, yet many others assume that it is ordinal data. The likert scale is widely used in social work research, and is commonly constructed with four to seven points. Almost everyone would recognise this type of survey.
Both ordinal and interval data are two of the four main data types or classifications used in statistics and other related fields. This includes not only likerttype scales but also other ordinal measures such as the rating of. In fact, we can measure the numerical distance of 4 from 5. Interval scales are numeric scales in which we know not only the order, but also the exact differences between the values. To determine the minimum and the maximum length of the 5point likert type scale, the range is calculated by 5. Likert scale examples for surveys iowa state university.
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