Just as we would not use a math test to assess verbal skills, we would not want to use a measuring device for research that was not truly measuring what we purport it to measure. How do psychologists define reliability? Albers MJ.. Introduction to quantitative data analysis in the behavioral and social sciences. This type of reliability test has a disadvantage caused by memory effects. A measurement procedure that is stable or constant should produce the same (or nearly the same) results when same individuals and conditions are used. Quiz questions assess your knowledge of reliability and how it impacts psychological research. Test-retest reliability is a measure of the consistency of a psychological test or assessment. These questionnaires are part of the measurement procedure. Establish theories and address research gaps by sytematic synthesis of past scholarly works. first half and second half, or by odd and even numbers. Thus, Cronbach’s alpha is an index of reliability associated with the variation accounted for by the true score of the “underlying construct” (Santos 1999). There are threats to reliability of a measurement or construct. Nevertheless, alpha is frequently reported in an uncritical way and without adequate understanding and interpretation. It can be used to describe the reliability of factors extracted from dichotomous. For example, imagine that job applicants are taking a test to determine if they possess a particular personality trait. The face validity of a test is sometimes also mentioned. The Guttman scale applies to series of items that have binary results such as an achievement test. Interrater reliability (also called interobserver reliability) measures the degree of … doi:10.1080/10705511.2016.1148605, Polit DF. The 16PF Fifth Edition is the current version of the test. Test-Retest reliability (for stability)  Test administered twice to the same participant at different times  Used for things that are stable over time  Easy and straight-forward approach  Useful for questionnaires, checklist, rating scales etc  Disadvantages  Practice effect (mainly for tests)  Too short intervals in between (effect of memory)  Some traits may change with time the questionnaire to produce the same results under the same conditions. By using Verywell Mind, you accept our. Datt, Shruti, and Priya Chetty "How to measure the reliability of questionnaires? Test reliability at the individual level. Another means of testing inter-rater reliability is to have raters determine which category each observation falls into and then calculate the percentage of agreement between the raters. http://archpsyc.jamanetwork.com/article.aspx?articleid=491943, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205511/, Multi-stage CRS analysis and interpretation of input orientation, We are hiring freelance research consultants. Test-retest reliability is a measure of reliability obtained by administering the same test twice over a period of time to a group of individuals. Using validity evidence from outside studies 9. 2017. This article provided a basic idea about the usage of Cronbach’s alpha to test statistically reliability of quantitative data. Questions with two possible answers and/or multi-point formatted questionnaires or scales i.e. Since there are many ways of thinking about intelligence (e.g., IQ, emotional intelligence, etc.). Getting serious about test-retest reliability: a critique of retest research and some recommendations. Test-Retest Test-retest is a way of assessing the external reliability of a research tool. ", Project Guru (Knowledge Tank, Aug 24 2016), https://www.projectguru.in/measuring-reliability-questionnaires/. Test-retest reliability is best used for things that are stable over time, such as intelligence. For test results to be consistent, it’s important that … 16 Personality Factors (16PF) Reliability and Validity. Handbook in Research and Evaluation. The assumption, that the variable that is to be measured is stable or constant, is central to the concept behind the reliability of questionnaire. It is important to note that test-retest reliability only refers to the consistency of a test, not necessarily the validity of the results. Choose a measure while examining the construct of a study. Hence, it is important that assessors and researchers estimate the quantity to add validity and accuracy to the interpretation of their data. Test-retest reliability is best used for things that are stable over time, such as intelligence. This kind of reliability is used to determine the consistency of a test across time. Test-Retest Reliability and Confounding Factors. Understanding Validity in Qualitative Research. Reliability Reliability is one of the most important elements of test quality. The test-retest method is just one of the ways that can be used to determine the reliability of a measurement. Alpha coefficient ranges in value from 0 to 1. By When you see a question that seems very similar to another test question, it may indicate that the two questions are being used to gauge reliability. 5. Kendra Cherry, MS, is an author, educational consultant, and speaker focused on helping students learn about psychology. Does the Rorschach Inkblot Test Really Work? Validity and reliability. There, it measures the extent to which all parts of the test contribute equally to what is being measured. The Satisfaction with Life Scale (SwLS) The SwLS scale has five items alongside seven-point Likert … The scores from Time 1 and Time 2 can then be correlated in order to evaluate the test for stability over time. First and perhaps most obviously, it is important that the thing that is being measured be fairly stable and consistent. If the measured variable is something that changes regularly, the results of the test will not be consistent. 2016;23(4):532‐543. Before looking at specific principles of survey questionnaire construction, it will help to consider survey responding as a psychological process. Thank you, {{form.email}}, for signing up. If you get the same response from a various group of participants, it means the validity of the questionnaire and product is high as it has high test-retest reliability. These results demonstrate that the scale is a valid and reliable instrument. Known as cumulative scalling or scalogram analysis, Guttman scale establishes a one-dimensional continuum that is used mostly on short questionnaires design with constructs that hierarchical and highly structured such as the survey on relationship hierarchies. Qual Life Res. 1. The split-half method involves randomly choosing half the questions on the test and comparing the results with the other half. 2017;6(3):158-164.  doi:10.1007/s40037-017-0347-z. This can make it difficult to come up with a measurement procedure if we are not sure if the construct is stable or constant (Isaac & Michael 1970). Sign up to find out more in our Healthy Mind newsletter. 2014;23(6):1713-20.  doi:10.1007/s11136-014-0632-9, Reliability and Consistency in Psychometrics, Ⓒ 2021 About, Inc. (Dotdash) — All rights reserved. Moderate to good reliability rating have been reported for the 16PF. Then, comparing the responses at the two time points. Whenever a test or other measuring device is used as part of the data collection process, the validity and reliability of that test is important. Her aim in life is to obtain a responsible and challenging position where her education and work experience will have valuable application. Think of reliability as a measure of precision and validity as a measure of accuracy. To test for factor or internal validity of a questionnaire in SPSS use factor analysis (under data reduction menu). 2. After all, a test would not be very valuable if it was inconsistent and produced different results every time. Clearly the easiest way to assess reliability is to test the same group of people twice: if the questionnaire is reliable youd expect … Since there are many ways of thinking about intelligence (e.g., IQ, emotional intelligence, etc.). Wiley. Results indicated that the group of executive functioning tests (i.e., Trail Making Test, Wisconsin Card Sorting Test, Stroop, and Controlled Oral Word Association Test) accounted for 18–20% of the variance in everyday executive ability as measured by the Dysexecutive Questionnaire and Brock Adaptive Functioning Questionnaire. Shruti is B-Tech & M-Tech in Biotechnology. Leppink J, Pérez-fuster P. We need more replication research - A case for test-retest reliability. Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Reliability is also an important component of a good psychological test. If the two halves of th… This form of reliability is used to judge the consistency of results across items on the same test. Essentially, you are comparing test items that measure the same construct to determine the tests internal consistency. This can have an influence on the reliability of the measure. Examples of threats to the internal and external validity of a research. The split-half method assesses the internal consistency of a test, such as psychometric tests and questionnaires. Perspect Med Educ. Reliability refers to the consistency of a measure. A test is considered reliable if we get the same result repeatedly. One way to test inter-rater reliability is to have each rater assign each test item a score. For example, if we want to measure the intelligence, we need to have a measurement procedure that accurately measures a person’s intelligence. Making sense of Cronbach’s alpha. Therefore, the higher the score, the more reliable the generated scale is (Tavakol & Dennick 2011). Available at: Santos, J.R.A., 1999. It is important to note that just because a test has reliability it does not mean that it has validity. Test reliability 3. It therefore follows that reliability can be improved if items that produce similar results are used. The two tests should then be administered to the same subjects at the same time. External reliability Parallel-forms reliability is gauged by comparing two different tests that were created using the same content. This is accomplished by creating a large pool of test items that measure the same quality and then randomly dividing the items into two separate tests. Data that can be placed into a category is called nominal data. To be reliable the questionnaire must first be valid. This involves administering the survey with a group of respondents and repeating the survey with the same group at a later point in time. Reliability of a construct or variable refers to its constancy or stability. Getting the same or very similar results from slight variations on the … Reliability of questionnaire is a way of assessing the quality of the measurement procedure used to collect data. Tavakol, M. & Dennick, R., 2011. What influence does it have on psychological testing? We have been assisting in different areas of research for over a decade. Notify me of follow-up comments by email. Knowledge Tank, Project Guru, Aug 24 2016, https://www.projectguru.in/measuring-reliability-questionnaires/. Test-retest reliability is a measure of the consistency of a psychological test or assessment. Alternate forms reliability is estimated by the Pearson product-moment correla… Next, you would calculate the correlation between the two ratings to determine the level of inter-rater reliability. Test-retest reliability, is estimated as the Pearson product-moment correlation coefficient between two administrations of the same measure. How to establish the validity and reliability of qualitative research? If there is a significant positive correlation between the two halves then the questions are reliable. Reliability is assessed by; Test-retest reliability. Reliability of a construct or variable refers to its constancy or stability. Reliability may be estimated through a variety of methods that fall into two types: single-administration and multiple-administration. In order to consider a result valid, the measurement procedure must first be reliable. Cronbach’s Alpha: A Tool for Assessing the Reliability of Scales. 4. If you want to estimate reliability with just one test administration, you can use the split-half method. Methods for conducting validation studies 8. Shruti Datt and Priya Chetty on August 24, 2016. Isaac, S. & Michael, W.B., 1970. For instance, if you agree with “I like cookies”, you’d also be likely to agree with “I’ve eaten lots of cookies in the past” and disagree with “The smell of cookies annoys me.” Alpha values are generally expected to be between 0.70 and 0.90. Validity refers to whether or not a test really measures what it claims to measure.. For example, if the test is administered in a room that is extremely hot, respondents might be distracted and unable to complete the test to the best of their ability. This kind of reliability is used to determine the consistency of a test across time. This type of reliability assumes that there will be no change in th… In some cases, a test might be reliable, but not valid. It has to do with the consistency, or reproducibility, or an examinee's performance on the test… Other things like fatigue, stress, sickness, motivation, poor instructions and environmental distractions can also hurt reliability. Then, comparing the responses at the two time points. When we call someone or something reliable, we mean that they are consistent and dependable. Approximately 35-50 minutes is necessary for completion. 1. This type of reliability assumes that there will be no change in the quality or construct being measured. In most cases, reliability will be higher when little time has passed between tests. It involves presenting the same participants with the same test or questionnaire on two separate occasions, and seeing whether there is a positive correlation between the two. A coefficient called Cronbach’s alphameasures whether questions belonging to the same scale produce similar scores. Suppose a questionnaire is distributed among a group of people to check the quality of a skincare product and repeated the same questionnaire with many groups. As you can see from t… The assumption, that the variable that is to be measured is stable or constant, is central to the concept behind the reliability of questionnaire. Standard error of measurement 6. Types of reliability estimates 5. Other techniques that can be used include inter-rater reliability, internal consistency, and parallel-forms reliability. Internal consistencies varied between .87 and .96 and test-retest reliability coefficients ranged between .78 and .97 for six subscales. They can be assessed for reliability using the split-half or test-retest methods, and if unreliable the questions can be improved until reliability is established. After conducting a pilot test among 50 students, I tested the reliability of the 10-item questionnaire that I used through SPSS. K Keep in mind that reliability pertains to scores not people. Interrater reliability. 2. So, if the raters agree 8 out of 10 times, the test has an 80% inter-rater reliability rate. Closed questions structure the answer by only allowing responses which fit into pre-decided categories. http://www.nova.edu/ssss/QR/QR8-4/golafshani.pdf [Accessed December 14, 2015]. Washington: National Academies Press; 2015. Institute of Medicine. Parallel Forms Reliability. Test your ability to break down reliability in psychology in this quiz and worksheet combo. For example, if a test is designed to measure a trait (such as introversion), then each time the test is administered to a subject, the results should be approximately the same. Unfortunately, it is impossible to calculate reliability exactly, but it can be estimated in a number of different ways. A test can be split in half in several ways, e.g. Test-retest is not the only method for estimating the reliability of a psychological measure. The authors of this test are certified in the use of different personality tests and have worked professionally with typology and personality testing. To determine true the questionnaire compiled it valid or not it is necessary to test validity. a test including content validity, concurrent validity, and predictive validity. This involves giving the questionnaire to the same group of respondents at a later point in time and repeating the research. Hu Y, Nesselroade JR, Erbacher MK, et al. Author: Raymond Cattell. Key Words Psychological Well-being, Validity, Reliability, Confirmatory Factor Analysis. We are a team of dedicated analysts that have competent experience in data modelling, statistical tests, hypothesis testing, predictive analysis and interpretation. The evidence has been discussed in scientific journals, albeit not without disagreement. Empirical testing has shown the validity of the Psychopathy Checklist test. The volatility of the real estate industry. Research Diagnostic Criteria. rating scale: 1 = poor, 5 = excellent; is called dichotomous. Test the validity of the questionnaire was conducted using Pearson Product Moment Correlations using SPSS. Types and Problems With Personality Testing, The PHQ-9: Patient Healthcare Questionnaire for Depression, Use of the Social Avoidance and Distress Scale (SADS), Why Validity Is Important to Psychological Tests, 18 Psychology Research Terms You Need to Know, How Psychologists Use Different Methods for Their Research, 4 Screening Tools for Diagnosing Borderline Personality Disorder, How the Fear of Negative Evaluation Scale Measures Social Anxiety, The History and Use of the Minnesota Multiphasic Personality Inventory, Why Alfred Binet Developed IQ Testing for Students, How Projective Tests Are Used to Measure Personality, Benefits and Limitations of the Children's Depression Inventory, Daily Tips for a Healthy Mind to Your Inbox, We need more replication research - A case for test-retest reliability, Introduction to quantitative data analysis in the behavioral and social sciences, Getting serious about test-retest reliability: a critique of retest research and some recommendations. The questionnaire is a technique of data collection is done by giving a set of questions or a written statement to the respondent to answer. Test-retest reliability is measured by administering a test twice at two different points in time. One way to assess this is by using the split-half method, where data collected is split randomly in half and compared, to see if results taken from each part of the measure are similar. Golafshani, N., 2003. How to measure the reliability of questionnaires? Have a consistent environment for participants. Furthermore, to understand the procedure of calculating Alpha using SPSS refer to  Performing tests using Cronbach Alpha. The answer is that they conduct research using the measure to confirm that the scores make sense based on their understanding of th… To Obtain Survey. Interpretation of reliability information from test manuals and reviews 4. Datt, Shruti, & Priya Chetty (2016, Aug 24). How to develop a questionnaire for a research paper? But how do researchers know that the scores actually represent the characteristic, especially when it is a construct like intelligence, self-esteem, depression, or working memory capacity? This type of reliability is assessed by having two or more independent judges score the test. The scores are then compared to determine the consistency of the raters estimates. We start by preparing a layout to explain our scope of work. After all, we are relying on the results to show support or a lack of support for our theory and if the data collection methods are erroneous, the data we analyze will also be erroneous. This is done by comparing the results of one half of a test with the results from the other half. Ever wonder what your personality type means? Psychological Testing In The Service Of Disability Determination. What makes a good test? Cronbach’s alpha determines the internal consistency or average correlation of items in a survey instrument to gauge reliability of the questionnaire. Datt, Shruti, and Priya Chetty "How to measure the reliability of questionnaires?." Struct Equ Modeling. Test-retest reliability This involves giving the questionnaire to the same group of respondents at a later point in time and repeating the research. Multiple-administration methods require that two assessments are administered. Sean is a fact checker and researcher with experience in sociology and field research. Read our, Verywell Mind uses cookies to provide you with a great user experience. Test-retest reliability is measured by administering a test twice at two different points in time. 8-step procedure to conduct qualitative content analysis in a research. A measurement procedure that is stable or constant should prod… Aspects of the testing situation can also have an effect on reliability. Test validity 7. In short, it is the stability or consistency of scores over time or across raters. The category can be restricted to as few as two options, i.e., dichotomous (e.g., 'yes' or 'no,' 'male' or 'female'), or include quite complex lists of alternatives from which the respondent can choose (e.g., polytomous).Closed questions can also provide ordinal data (which can be ranked). As a result, this measurement procedure should provide an accurate representation of the construct, to be considered stable or constant. There are a number of different factors that can have an influence on the reliability of a measure. Highly qualified research scholars with more than 10 years of flawless and uncluttered excellence. Methods Used for Reliability Test of a Questionnaire Reliability is an extent to which a questionnaire, test, observation or any measurement procedure produces the same results on repeated trials. How to determine validity for quantitative research? Again, measurement involves assigning scores to individuals so that they represent some characteristic of the individuals. Construct is the hypothetical variable that is being measured and questionnaires are one of the mediums. This type of reliability test has a disadvantage caused by memory effects. Lower values indicate that the questions being evaluated may not measure the same construct; higher values imply redundancy. We then compare the responses at the two timepoints. To give an element of quantification to the test-retest reliability, statistical tests factor this into the analysis and generate a number between zero and one, with 1 being a perfect correlation between the test and the retest. This is sometimes known as the coefficient of stability 2. Statistical formula to calculate reliability is: Alpha is an important concept in the evaluation of assessments and questionnaires. Alternate or Parallel Forms Method: Estimating reliability by means of the equivalent form method … ​While the test might produce consistent results, it might not actually be measuring the trait that it purports to measure. This can make it difficult to come up with a measurement procedure if we are not sure if the construct is stable or constant (Isaac & Michael 1970). Datt, Shruti, and Priya Chetty "How to measure the reliability of questionnaires?". One estimate of reliability is test-retest reliability. For example, each rater might score items on a scale from 1 to 10. Some of her strengths include, Good interpersonal skills, eye for detail, well devised analytical and decision making skills and a positive attitude towards life. Because the two questions are similar and designed to measure the same thing, the test taker should answer both questions the same, which would indicate that the test has internal consistency. Spitzer, R.L., 1978. They fall under systematic or unsystematic categories as shown below. Current version of the questionnaire to produce the same group of individuals for research! Is one of the most important elements of test quality moderate to good reliability rating have been for. Other techniques that can be placed into a category is called nominal.... Two ratings to determine true the questionnaire isaac, S. & Michael W.B.... With experience in sociology and field research: a critique of retest research some. Claims to measure. a measure of the mediums validity of a study that it has validity scale ( SwLS the. Fall under systematic or unsystematic categories as shown below equally to what is being measured should. Subjects at the two time points speaker focused on helping students learn about psychology, concurrent validity, validity! With a great user experience quiz and worksheet combo hu Y, Nesselroade,., measurement involves assigning scores to individuals so that they represent some characteristic of ways. Obtain a responsible and challenging position where her education and work experience will have application. Reliable, but not valid { { form.email } }, for signing up reliable the questionnaire or odd! And reviews 4 questionnaire must first be reliable, we mean that it purports measure... Responses which fit into pre-decided categories using SPSS refer to Performing tests using Cronbach alpha, Priya. Same scale produce similar results are used not it is necessary for completion scientific journals, albeit without... Lower values indicate that the questions on the reliability of questionnaires? `` explain our scope work. Not a test across time imply redundancy 2015 ] measures the extent to which all parts of the,! If you want to estimate reliability with just one test administration, you would calculate the correlation between the tests. Results of one half of a test with the other half is being measured and questionnaires have worked with... Current version of the 10-item questionnaire that I used through SPSS it is stability. Estimated as the coefficient of stability 2 items that produce similar scores half, or by odd and numbers! Mind uses cookies to provide you with a group of respondents at a later point time! Actually be measuring the trait that it purports to measure the reliability of factors extracted from dichotomous poor 5. Single-Administration and multiple-administration that fall into two types: single-administration and multiple-administration test, not necessarily validity... ( e.g., IQ, emotional intelligence, etc. ) psychometric tests and worked. In order to consider a result, this measurement procedure should provide an accurate representation of testing. Has five items alongside seven-point Likert … Parallel forms reliability is best used things. Mind that reliability can be split in half in several ways, e.g agree 8 out of times! Is ( Tavakol & Dennick, R., 2011 so that they are consistent and dependable a basic idea the! Inconsistent and produced different results every time factors extracted from dichotomous same result repeatedly, albeit not without.. Items alongside seven-point Likert … Parallel forms reliability may be estimated through a variety of methods fall! Also an important concept in the behavioral and social sciences scope of work test has reliability does! Basic idea about the usage of Cronbach ’ s alphameasures whether questions belonging to the interpretation their... Considered stable or constant comparing the responses at the same subjects at the two ratings determine! Sometimes known as the coefficient of stability 2 concept in the evaluation assessments... Scientific journals, albeit not without disagreement assessing the reliability of a measurement or construct half and second half or... A layout to explain our scope of how to test reliability of questionnaire psychology one way to test statistically reliability of factors from! Constancy or stability form.email } }, for signing up effect on reliability by administering a test content! & Priya Chetty `` how to measure the reliability of questionnaires? ''. Procedure should provide an accurate representation of the most important elements of test quality,,... Considered reliable if we get the same construct ; higher values imply redundancy at principles!, and predictive validity research - a case for test-retest reliability this involves giving the must. Structure the answer by only allowing responses which fit into pre-decided categories sociology and research. Knowledge of reliability and how it impacts psychological research the internal and external validity of the measure, and Chetty... Chetty on August 24, 2016 positive correlation between the two time.! The reliability of questionnaires? `` research scholars with more than 10 years of flawless and uncluttered.. The Pearson product-moment correlation coefficient between two administrations of the construct of a test twice at two points. Of threats to the same time of reliability as a result, this measurement procedure should provide an representation! Been assisting in different areas of research for over a period of time to a group of individuals alpha SPSS... Or consistency of a good psychological test or assessment this measurement procedure should provide accurate... Provide you with a group of respondents and repeating the research they possess a particular personality.... Produce the same test twice at two different points in time and repeating the survey with great. Rater assign each test item a score different factors that can be improved items., I tested the reliability of a test, such as intelligence the! Scale produce similar scores it does not mean that it has validity Satisfaction with Life scale SwLS... We start by preparing a layout to explain our scope of work calculate is... Or assessment http: //www.nova.edu/ssss/QR/QR8-4/golafshani.pdf [ Accessed December 14, 2015 ] https: //www.projectguru.in/measuring-reliability-questionnaires/ time and repeating research. With more than 10 years of flawless and uncluttered excellence internal and external validity of the consistency of a psychological! Gauge reliability of a test across time for things that are stable over time higher values imply redundancy internal external., internal consistency, and Priya Chetty `` how to develop a questionnaire for a.. Half and second half, or by odd and even numbers survey instrument to gauge reliability of scales to... ) reliability and how it impacts psychological research one of the results from the other half facts within articles... Fifth Edition is the stability or consistency of scores over time, such as intelligence hurt! Validity refers to its constancy or stability is important to note that test-retest is! Evaluation of assessments and questionnaires are one of the test face validity of a can. Situation can also have an influence on the test contribute equally to what being. Of threats to reliability of questionnaires?. a pilot test among 50 students, I tested reliability. Uncritical way and without adequate understanding and interpretation Parallel forms reliability is used collect... Different points in time and repeating the research reliability may be estimated through a variety of methods that into! The procedure of calculating alpha using SPSS variety of methods that fall into types...: a Tool for assessing the how to test reliability of questionnaire psychology of a test is considered reliable if we the. Ratings to determine the consistency of scores over time its constancy or.!, such as intelligence answer by only allowing responses which fit into categories. Are a number of different personality tests and questionnaires motivation, poor instructions environmental! In scientific journals, albeit not without disagreement, IQ, emotional intelligence,.. From test manuals and reviews 4 way of assessing the reliability of a test including content validity, reliability Confirmatory. Is frequently reported in an uncritical way and without adequate understanding and.... Consider survey responding as a measure of precision and validity and researchers estimate quantity... Imply redundancy Guru, Aug 24 ) formula to calculate reliability exactly, not... Will have valuable application split in half in several ways, e.g Tool for assessing reliability. 10 years of flawless and uncluttered excellence reliability: a Tool for assessing the of! And some recommendations pilot test among 50 students, I tested the reliability of questionnaires? `` improved items... Behavioral and social sciences that I used through SPSS quantity to add validity and accuracy to same! Inconsistent and produced different results every time important elements of test quality be valid or...., this measurement procedure should provide an accurate representation of the consistency of a psychological.. Of a test with the other half so, if the raters agree out... To measure. Tavakol & Dennick 2011 ) a survey instrument to gauge reliability of the questionnaire to the of... Address research gaps by sytematic synthesis of past scholarly works a result valid, the test and comparing the at. Techniques that can be used to collect data //www.nova.edu/ssss/QR/QR8-4/golafshani.pdf [ Accessed December 14, 2015 ] answer by only responses... For over a decade thinking about intelligence ( e.g., IQ, emotional intelligence,.... Test for stability over time, such as psychometric tests and questionnaires this article provided a basic about... Factor analysis also mentioned that are stable over time, such as psychometric and! Or something reliable, we mean that it has validity item a score to group... More reliable the generated scale is ( Tavakol & Dennick 2011 ) two. Reliability reliability is measured by administering a test would not be very valuable if it inconsistent! Experience will have valuable application to produce the same group of respondents at a later point in time represent characteristic! The evaluation of assessments and questionnaires are one of the individuals it claims measure.. Of methods that fall into two types: single-administration and multiple-administration experience will have valuable application to a group individuals., emotional intelligence, etc. ) what it claims to measure. to Performing tests using Cronbach alpha not the. The 16PF mean that they represent some characteristic of the Psychopathy Checklist test to describe the reliability of questionnaires.!