Are Likert scales ordinal or interval scales?
What is Likert Scale Data Analysis? This scale is widely used in measuring the responses to the questionnaire in a research survey or aptitude test. It is The survey process involves the design of line items or individual questions, the list of responses options for each The list of responses. 3. Likert scale. A Likert scale is composed of a series of four or more Likert-type items that represent similar questions combined into a single composite score/variable. Likert scale data can be analyzed as interval data, i.e. the mean is the best measure of central tendency. Inference.
It is the most widely used approach to scaling responses in survey research, such that the term or more fully the How to copy a dvd-r scale is often used interchangeably with rating scalealthough there are other types of rating scales.
The scale is named after its inventor, psychologist Rensis Likert. Technically speaking, a Likert scale refers only to the former. When responding to a Likert item, respondents specify their level of agreement or disagreement on a symmetric agree-disagree scale for a series of statements. Thus, the range captures the intensity of their feelings for a given item.
A scale can be created as the simple sum or average of questionnaire responses over the set of individual items questions. In so doing, Likert scaling assumes distances between each choice answer option are equal.
Many researchers employ a set of such items that are highly correlated that show high internal consistency but also that together will capture the full domain under study which requires less-than perfect correlations. Others hold to a standard by which "All items are assumed to be replications of each other or in other words items what type of data is likert scale considered to be parallel instruments". A Likert scale is the sum of responses on several Likert item s.
Because many Likert scales pair each constituent Likert item with its own instance of a visual analogue scale e. Well-designed Likert items exhibit both "symmetry" and "balance". Balance means that the distance between each candidate value is the same, allowing for quantitative comparisons such as averaging to be valid across items containing more than two candidate values. Likert scaling is a bipolar scaling methodmeasuring either positive what type of data is likert scale negative response to a statement.
Sometimes an even-point scale is used, where the middle option of "neither agree nor disagree" is not available. This is sometimes called a "forced choice" method, since the neutral option is removed. A study found negligible what type of data is likert scale between the use of "undecided" and "neutral" as the middle option in a five-point Likert scale.
Likert scales may be subject to distortion from several causes. Respondents may:. Designing a scale with balanced keying an equal number of positive and negative statements and, especially, an equal number of positive and negative statements regarding each position or issue in question can obviate the problem of acquiescence bias, since acquiescence on positively keyed items will balance acquiescence on negatively keyed items, but defensive, central tendency, and social desirability biases are somewhat more problematic.
After the questionnaire is completed, each item may be analyzed separately or in some cases item responses may be summed to create a score for a group of items.
Hence, Likert scales are often called summative scales. Whether individual Likert items can be considered as interval-level data, or whether they should be treated as ordered-categorical data is the subject of considerable disagreement in the literature,   with strong convictions on what are the most applicable methods.
This disagreement can be traced back, in many respects, to the extent to which Likert items are interpreted as being ordinal data. There are two primary considerations in this discussion. First, Likert scales are arbitrary. The value assigned to a Likert item has no objective numerical basis, either in terms of measure theory or scale from which a distance metric can be determined.
The value assigned to each Likert item is simply determined by the what type of data is likert scale designing the survey, who makes the decision based on a desired level of detail. However, by convention Likert items tend to be assigned progressive positive integer values.
Likert scales typically range from 2 to 10 Ч what type of data is likert scale 3, 5, or, 7 being the most common. This may differ in cases where reverse ordering of the Likert Scale is needed. The second, and possibly more important point, is whether the "distance" between each successive item category is equivalent, which is inferred traditionally.
In terms of good research practice, an equidistant presentation by the researcher is important; otherwise a bias in the analysis may result. For example, a four-point Likert item what type of data is likert scale categories "Poor", "Average", "Good", and "Very Good" is unlikely to have all equidistant categories since there is only one category that can receive a below-average rating. This would arguably bias any result in favor of a positive outcome. On the other hand, even if a researcher presents what he or she believes are equidistant categories, it may not be interpreted as such by the respondent.
A good Likert scale, as above, will present a symmetry of categories about a midpoint with clearly defined linguistic qualifiers. In such symmetric scaling, equidistant attributes will typically be more clearly observed or, at least, inferred.
It is when a Likert scale is symmetric and equidistant that it will behave more like an interval-level measurement. So while a Likert scale is indeed ordinalif well presented it may nevertheless approximate an interval-level measurement.
The important idea here is that the appropriate type of analysis is dependent on how the Likert scale has been presented. Notions of central tendency are often applicable at the item level Ч that is responses often show a quasi-normal distribution. The validity of such measures depends on the underlying interval nature of the scale. If interval nature is assumed for a comparison of two groups, the paired samples t -test is not inappropriate.
Responses to several Likert questions may be summed providing that all questions use the how to permanently delete files after recycle bin Likert scale and that the scale is a defensible approximation to an interval scale, in which case the central limit theorem allows treatment of the data as interval data measuring a latent variable.
Typical cutoffs for thinking that this approximation will be acceptable is a minimum of four and preferably eight items in the sum.
To model binary Likert responses directly, they may be represented in a binomial how to fit decking newel posts by summing agree and disagree responses separately.
The chi-squaredCochran's Q testor McNemar test are common statistical procedures used after this transformation. Non-parametric tests such as chi-squared testMannЧWhitney testWilcoxon signed-rank testor KruskalЧWallis test. Alternatively, Likert scale responses can be analyzed with an ordered probit model, preserving the ordering of responses without the assumption of an interval scale. The use of an ordered probit model can prevent errors that arise when treating ordered ratings as interval-level measurements.
How do doctors test for blood clots assessment CBA can be used to create an objective standard for Likert scales in domains where no generally accepted or objective standard exists. Consensus-based assessment CBA can be used to refine or even validate generally accepted standards.
An important part of data analysis and presentation is the visualization or plotting of data. The subject of plotting Likert and other rating data is discussed at length in two papers by Robbins and Heiberger. The second paper  describes the use of the Likert function in the HH package for R, and gives many examples of its use. The five response categories are often believed to represent an interval level of measurement.
But this can only be the case if the intervals between the scale points correspond to empirical observations in a metric sense. Reips and Funke  show that this criterion is much better met by a visual analogue scale. In fact, there may also appear phenomena which even question the ordinal scale level in Likert scales. This violates the axiom of transitivity for the ordinal scale. Research by Labovitz  and Traylor  provide evidence that, even with rather large distortions of perceived distances between scale points, Likert-type items perform closely to scales that are perceived as equal intervals.
So these items and other equal-appearing scales in questionnaires are robust to violations of the equal distance assumption many researchers believe are required for parametric statistical procedures and tests. Likert scale data can, in principle, be used as a basis for obtaining interval level estimates on a continuum by applying the polytomous Rasch modelwhen data can be obtained that fit this model.
In addition, the polytomous Rasch model permits testing of the hypothesis that the statements reflect increasing levels of an attitude or trait, as intended. For example, application of the model often indicates that the neutral category does not represent a level of attitude or trait between the disagree and agree categories. Again, not every set of Likert how to deal with baby constipation items can be used for Rasch measurement.
The data has to be thoroughly checked to fulfill the strict formal axioms of the model. However, the raw scores are the sufficient statistics for the Rasch measures, a deliberate choice by Georg Raschso, if you are prepared to accept the raw scores as valid, then you can also accept the Rasch measures as valid.
From Wikipedia, the free encyclopedia. Psychometric measurement scale. Historical perspectives. Conflict theory Structural functionalism Positivism Social constructionism. Borg scale Bogardus social distance scale Diamond of opposites Discan scale K-factor Guttman scale Ipsative Mokken scale Phrase completion scales Questionnaire Questionnaire construction Rating scale Rating sites Rosenberg self-esteem scale Satisficing Semantic differential Thurstone scale Voting system.
October 4, East Carolina University. Retrieved April 30, Retrieved 28 February Archives of Psychology. Summated Rating Scale Construction. International Journal of Mathematics and Statistics.
Journal of Social Sciences. Basic Marketing Research Second ed. New Jersey: Pearson Education. ISBN Retrieved 9 March Nothing is more applicable than good theory". Journal of Advanced Nursing.
PMID Quality Progress. Perceptual and Motor Skills. Medical Education. Advances in Health Science Education. Retrieved 13 August Journal of the American Statistical Association. Learning Technology Dissemination Initiative. Heriot-Watt University. Journal of Experimental Social Psychology. American Statistical Association.
Are Likert Scales Ordinal or Interval?
Jul 03, †Ј A Likert scale is a rating scale used to assess opinions, attitudes, or behaviors. Likert scales are popular in survey research because they allow you . Jun 03, †Ј A Likert scale is a close-ended, forced-choice scale. It provides quantitative data that can easily be analyzed. Feb 20, †Ј Likert scales give quantitative value to qualitative data. For example, it may be designed to measure how much a person agrees with a statement regarding a productТs value and assigns a data point to it. This is one reason why the scale is almost universally loved.
Two thumbs up! Five stars! There are many types of scales designed to let the public know the quality of something. So what is a Likert scale? How do you use one? Create your Likert-based survey, form, or poll now! The Likert scale is named after American social scientist Rensis Likert. Likert devised the psychometric approach in for conducting social and educational research. Today, Likert-type scales are considered some of the best survey tools for researching popular opinions. In a Likert scale , a person selects one option among several that reflects how much they agree with a statement.
The scale generally consists of five or seven balanced responses that people can choose from, with a neutral midpoint. However, there can be as few as two responses with no neutral response or as many as ten. Almost everyone agrees that the Likert rating scale provides ordinal data data which is measured along a scale, but the distances between each point is unknown. However, many believe this scale also provides interval data data which is measured along a scale, with each point placed at equal distances from one another.
For example, we know that a 4 is better than a 3. That said, when a survey has enough questions, many researchers use the data to come up with reliable averages. We think Dr. David L. Likert scales give quantitative value to qualitative data. This is one reason why the scale is almost universally loved. Researchers like that Likert rating scale questions use a universal method of collecting data, so the results can be easily understood.
There are Likert scale advantages and disadvantages. However, there are many more pros than cons! Likert scales are easy for people to understand and complete. Instead, they can choose to be neutral. All of this means that they wind up delivering better response rates! Consider a restaurant. Sure, you may know someone is dissatisfied with your restaurant because they only gave you one star.
The service? After that, ask for their overall satisfaction level. Most researchers agree that the best Likert scales are the 5-point and 7-point varieties. This simply refers to how many responses the person has to choose from.
Most Likert scales you see are going to be odd-numbered. They will have an equal number of positive and negative responses on either side of a neutral response. So why are 5 point and 7 point considered ideal? On the other hand, if you go above seven, respondents may feel overwhelmed or annoyed; they may just pick a random answer to move along quickly.
This version forces respondents to make a choice. Consider this 4 point smiley face Likert scale, where the faces represent: Extremely Dissatisfied, Somewhat Dissatisfied, Satisfied, and Extremely Satisfied:. There is no neutral choice. However, if a researcher wants to find a neutral point, they can average together Somewhat Dissatisfied and Satisfied. The 6 point scale is meant to provide more options for respondents.
Because it is an even point scale, there is no neutral option. This Likert scale is used to offer respondents a wider variety of choices. It provides a higher degree of measurement precision, with a neutral option. As noted before, this can result in them being less accurate with responses as they speed through the survey. This provides a greater Likert scale level of measurement precision, like the 9 point Likert scale.
However, it does not include a neutral option. Asking multiple questions remedies this, taking into consideration all of the factors that could have contributed to this response. Mixing different scales within your surveys can cause respondent confusion. Bonus: Using only one scale will also make your final analysis that much easier. Do not simply attach a number to possible responses. Always include wording on your scale question , otherwise online survey takers may confuse which numbers are positive and which are negative.
To improve Likert scale validity and reliability, stay away from survey questions that may lead people to answer a certain way. In fact, the best survey questions are concise and to-the-point. Long, complex questions, for instance, tend to lose readers or test their patience. Additionally, inadvertently asking two questions in one can leave respondents unsure of how to answer. Below are a number of examples of Likert scales using different numbers of points. The Likert scale question examples may also provide inspiration when developing your survey.
Please note that the numbers in the answers indicate the relative position of items, but not the magnitude of difference. You do not have to include numbers in your survey questions if you prefer not to.
You will find many ideas out there about how to analyze Likert scale data. For example, many people want to know how to calculate mean score for Likert scale data, which would simply be the sum of all numbers divided by the count. However, as mentioned earlier, these scales provide ordinal data, and the values between points cannot be considered equal. That means that using a mean the average of all the numbers is not appropriate for analysis.
Instead, it is recommended that you use a mode score for easy inappropriate for ordinal data. To calculate the mode score for Likert scale data, simply determine the number that appears the most. The mode would be 4, as it appears the most.
Here, the mode would be 1. However, the mean would have been 3, but concluding that most people think the product is average is clearly not the case, which is why a mode score is most appropriate when analyzing Likert scale data.
The Likert scale is a great option for businesses and researchers wanting an easy way to survey customers or the general public. Have you used a Likert scale in your research?
Did you find it easy to use and analyze? Let us know in the comments! Likert scales measure how much a person agrees with a statement. Likert scales provide ordinal data data which is measured along a scale, but the distances between each point are unknown. They assign a data point to a statement. But how While customer experience may be king, product experience is just as David J. Sign up, it's free! Are Likert Scales Ordinal or Interval?
Why Use a Likert Scale? Advantages and Disadvantages There are Likert scale advantages and disadvantages.
Other Point Variations in Likert Scales While the 5 point and 7 point Likert scale are most popular, there are other variations. Consider this 4 point smiley face Likert scale, where the faces represent: Extremely Dissatisfied, Somewhat Dissatisfied, Satisfied, and Extremely Satisfied: There is no neutral choice.
Avoid using different scales Mixing different scales within your surveys can cause respondent confusion. Label the numeric responses Do not simply attach a number to possible responses. Create unbiased responses To improve Likert scale validity and reliability, stay away from survey questions that may lead people to answer a certain way.
Likert Scale Examples and Questions Below are a number of examples of Likert scales using different numbers of points.
Barriers 1 Ч Not a barrier 2 Ч Somewhat of a barrier 3 Ч Moderate barrier 4 Ч Extreme barrier. Level of Familiarity 1 Ч Not at all familiar 2 Ч Slightly familiar 3 Ч Somewhat familiar 4 Ч Moderately familiar 5 Ч Extremely familiar.
Level of Awareness 1 Ч Not at all aware 2 Ч Slightly aware 3 Ч Somewhat aware 4 Ч Moderately aware 5 Ч Extremely aware. Knowledge of Action 1 Ч Never true 2 Ч Rarely true 3 Ч Sometimes but infrequently true 4 Ч Neutral 5 Ч Sometimes true 6 Ч Usually true 7 Ч Always true. Level of Appropriateness 1 Ч Absolutely inappropriate 2 Ч Inappropriate 3 Ч Slightly inappropriate 4 Ч Neutral 5 Ч Slightly appropriate 6 Ч Appropriate 7 Ч Absolutely appropriate.
Level of Importance 1 Ч Not at all important 2 Ч Low importance 3 Ч Slightly important 4 Ч Neutral 5 Ч Moderately important 6 Ч Very important 7 Ч Extremely important. Level of Concern 1 Ч Not at all concerned 2 Ч Slightly concerned 3 Ч Somewhat concerned 4 Ч Moderately concerned 5 Ч Extremely concerned. Level of Influence 1 Ч Not at all influential 2 Ч Slightly influential 3 Ч Somewhat influential 4 Ч Moderately influential 5 Ч Extremely influential.
Level of Agreement 1 Ч Strongly disagree 2 Ч Disagree 3 Ч Somewhat disagree 4 Ч Neither agree or disagree 5 Ч Somewhat agree 6 Ч Agree 7 Ч Strongly agree. Level of Satisfaction 1 Ч Completely dissatisfied 2 Ч Mostly dissatisfied 3 Ч Somewhat dissatisfied 4 Ч Neither satisfied or dissatisfied 5 Ч Somewhat satisfied 6 Ч Mostly satisfied 7 Ч Completely satisfied.