Uimportant to assess for the scale no matter how the items are combined, although the decision about whether the reliability of a set of items is acceptable is a different ball game when factor analysis score coefficients have been used. Scales are sets of items measuring similar constructs on questionnaires. Key learnings from the cognitive interviews informed the revision and simplification of several survey items. No cfa was conducted to confirm this twofactor model, however. I specified 6 factors ahead of time based on a parallel analysis and suppressed coefficients items included 8 reverse coded items, and all 8 of these loaded on one factor and no other items did. Factor structure and measurement invariance of the womens health initiative insomnia rating scale. Whether to use original or reverse coded items in factor analysis. This confirmatory factor analysis allowed the authors to quantitatively test their theoretical model pintrich et al. This study examined the effect of the rw items on the factor structure of the abbreviated 18item need for cognition nfc scale.
Responses to the original and revised job diagnostic survey. Whether to use original or reverse coded items in factor. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is made up of multiple likerttype scales and items. Factor analysis of caregiver strain questionnaire in clinical research hui liu and david shen, clinforce, llc, king of prussia, pa abstract caregiver strain questionnaire cgsq is expected to have multiple dimensions. Factor structure and measurement invariance of the womens. The exploratory factor analysis on a random half of the sample predicted a 33item five factor solution, whereas the confirmatory factor analysis on the remaining. Sep 22, 2017 exploratory factor analysis efa is then conducted on the responses to the preliminary items, to identify the factor structure within the items and thus the preliminary psychometric scales. For example, lets say that item 1 and item 2 should load on the same factor, but item 2 is reverse scored. Social relationships, leisure activity, and health in. This accuracy problem was inferred based on the assumption that raters scores on the negatively worded item in each scale should after it was recoded be. What is your opinion about reverse coded items in a. Because it concerns reliability in measuring an unobserved factor, is related to factor analysis.
Andy field page 2 2152006 therefore, if you have reverse phrased items then you have to also reverse the way in which theyre scored before you conduct reliability analysis. After the rw items have been reversecoded, the total scale score is then presumed to be biasfree. Ipip, fivefactor model of personality, confirmatory factor analysis, m550 goldberg s. Some irt functions require all items to be coded in the same direction. The test should be designed to measure one factor, and, because the scale will be composed of an. In spss, when you calculate the cronbach alpha, there is an option to ask for each item what would alpha be if that item were deleted. Reliability analysis example portland state university. Uwhen running reliability on spss use scalereliability analysis, make sure all items are coded in the same direction i. Is education a factor in responses to negatively worded items.
In the item evaluation 5point likert type scale was used never1 to always5. The real scale or the reversed scale to do the analysis. Reverse worded rw items are often used to reduce or eliminate acquiescence. This means that if you have a mixture of reverse coded and non reverse coded items, using this method to reverse code your items will mean that some items have the most negative choice presented first, while other items will have the most positive choice presented first. Examining the effect of reverse worded items on the factor. So for example lets say you have 20 items each on a 1 to 7 scale. Review of the mslq 8 identification of which items indicators should fall onto which factors latent variables. This omission can complicate the outcome and hence obscure the discovery of interesting factors. However, a major issue was that the reverse coded items clearly caused problems for 1020% of the raters, who did not seem to rate them accurately. The basic procedures of efa are detailed in many statistical textbooks see, e. Our framework distinguishes three sources of reversed item bias. I need a clarification regarding reverse coding of. While a complete presentation and discussion of the factor analysis results.
Items were recoded in the factor analysis as well as in the final data set so that a high mean score signified more. Our findings indicate the need to further examine the construct validity of the. Reverse the coding of selected items prior to scale analysis. Before you run a cronbachs alpha or factor analysis on scale items, its generally a good idea to reverse code items that are negatively worded so that a high value indicates the same type of response on every item. An easy way to reverse code scale items the analysis factor. The items within a scale are typically interchangeable, meaning that the response to.
Convergent and discriminant validity and common method bias kuba glazek, ph. These are exactly the items with negative factor loadings when one factor is extracted using maximumlikelihood throughout this section from the cdi item responses of the abc data. Faces consists of two scales with eight of its 30 items reverse coded. From what i have read in the literature, the value of reverse coding items seems to be related to reducing or eliminating. Exploratory factor analysis efa is then conducted on the responses to the preliminary items, to identify the factor structure within the items and thus the preliminary psychometric scales.
In scale construction, is reversescoring some items desirable or not. Therefore, results obtained via traditional covariance analyses may be distorted. Two reversecoded items items 2 and 4 were removed due to insufficient factor loadings, resulting in the modified 21item sir sir21. As gung said, recoding reverse scored variables will only reverse the sign of their factor loadings, so the decision is only important because you will have to keep track of and specify in anything you write about it which variables are reverse scored, or whether you recoded them. In summary, the use of rw items in likert scales, while extremely. Based upon exploratory factor analysis suggesting a common latent factor eigenvalue 1. Original article prevalence and frequency of internet. In scale construction, is reversescoring some items. I specified 6 factors ahead of time based on a parallel analysis and suppressed coefficients is reversescoring some items desirable or not. Factor analysis with the test sample has confirmed that the swls. The current article was written in order to provide a simple resource for. However, it is often the case that the respondents react differently to positive and negative formulated items.
For example, lets say that item 1 and item 2 should load on the same factor, but. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is. To judge whether item content reflected sleep disturbance, consider how the items match the nosologies. There were three items that were negatively keyed that needed to be rescored. Ipip, five factor model of personality, confirmatory factor analysis, m550 goldberg s international personality item pool ipip. Principalaxes factor analysis without iteration and rotation to a. As gung said, recoding reversescored variables will only reverse the sign of their factor loadings, so the decision is only important because you will have to keep track of and specify in anything you write about it which variables are reversescored, or whether you recoded them. Parent survey development the parent survey was designed to collect parent report of their childrens civic engagement and character strengths. Factor analysis is a deceptively difficult technique to conduct appropriately. However, the wisdom of introducing rw items into scales has recently been. University of northern colorado abstract exploratory factor analysis efa investigates the possible underlying factor structure dimensions of a set of interrelated variables without imposing a preconceived structure on the outcome child, 1990. Many researchers undertake factor analysis without eliminating unsuitable items in advance. Besides, reverse coded items cause confusion in participants and distract the harmony. The seven reverse coded items are measured on a likerttype scale ranging from 1 strongly agree to 5 strongly disagree.
This has the benefit of simplifying data analysis, especially if your items responses are ordinal. Factor analysis results negative loadings and reverse. How to reverse score questions questionnaires that use a likert scale eg. There have been several clients in recent weeks that have come to us with binary survey data which they would like to factor analyze. The goal of this whole procedure is to produce a single score for your questionnaire. In this process, the following facets will be addressed, among others.
Factor analysis metaanalysis discriminant validity degree to which an instrument does not measure other constructs. Responses to these items from 74 male college students are in this spss data file, which you should download and open reverse scoring. What is your opinion about reverse coded items in a questionnaire. Syntax alpha varlist if in, options options description options. For most items, a 7 may indicate a positive attitude toward some issue, but for a few items, a 1.
Reverse worded rw items are often used to reduce or eliminate acquiescence bias, but there is a rising concern about their harmful effects on the covariance structure of the scale. This example comes from a set of items my class developed to measure internet addiction. Most of the items are phrased so that strong agreement indicates a belief that men should protect women, that men need women, and that women have positive qualities that men lack. It is important to make the language of your reverse coded items as. From what i have read in the literature, the value of reverse coding items seems to be. I had reverse coded those items prior to running the cfa, but a previous question did suggest i am correct to do this, so what might be the issue here. The analysis is based on the empirical inconsistency between the reversed and the positively worded items. It is recommended that you check your questionnaire with confirmatory factor analysis cfa, in order to secure that all items in the scale are well choosen for the scale. The current article was written in order to provide a simple resource for others who may. May 07, 20 reverse the coding of a variable using spss. This means that if you have a mixture of reversecoded and nonreverse coded items, using this method to reversecode your items will mean that some items have the most negative choice presented first. Items were recoded in the factor analysis as well as in the final data set so that a high mean score signified more positive levels related to the specific dimension of.
However, in a factor analysis, all the reverse coded items load onto one factor when they actually should load onto four separate ones. Syntax data analysis and statistical software stata. The satisfaction with life scale is in the public domain. Items in brown are those not in the qol scale for older adults. Scoring for the neighborhood environment walkability scale. Factor analysis model evaluation through likelihood cross. Cdi consists of a single scale with of its items reverse coded. These items were reverse coded to be consistent with the other items.
Parent survey items directly mirrored youth items when appropriate. For example, in a selfesteem questionnaire we may have some positively worded questions eg. Reversecoded items tend to load on a separate factor, a method factor. Factor analyses of scales that contain items written in opposite directions. Confirmatory factor analysis indicated reasonably good model fit. Researchers who wish to measure personality would be well advised to consider using the m550. Menu statistics multivariate analysis cronbachs alpha description alpha computes the interitem correlations or covariances for all pairs of variables in varlist and cronbachs statistic for the scale formed. How to reverse score questions york st john university. Calculate the average answer of reversecoded items, and the.
A factor analysis for all social support and strain and the concepts of main effect model supported combining this overall latent variable for two support and strain items. Before you run a cronbachs alpha or factor analysis on scale items, its generally a good idea to reverse code items that are negatively worded so that a high value indicates the same type of response on every item so for example lets say you have 20 items each on a 1 to 7 scale. Factor analysis results negative loadings and reverse coded. Empirical support for a twofactor model has been inconsistent. Examination of meyer and allens affective and continuance commitment scales using confirmatory factor analysis with lisrel 7 provided strong support across multiple diagnostics for the existence of a reverse coding method factor defined by the six negatively worded items in the scales. No cfa was conducted to confirm this twofactor model. The development and testing of the nursing teamwork survey. It was the aim of this study to investigate and confirm the dimensional structure of cgsq measured from subjects. The selfscoring table is also available in appendix b. Paper 3312012 exploratory factor analysis with the world values survey diana suhr, ph. Specifically, if at least 10% of respondents are careless, a clearly identifiable method component emerges from principal component analysis pca. How to analyse questionnaire with negative item reverse item and. How to analyse questionnaire with negative item reverse. Item deletion before factor analysis dr simon moss.
The gpi includes eight items that are reverse coded before the calculation of the gpi scales. More directly, if you do a principal components analysis, the inverse coded items will load negatively on the principal components, which would suggest that reverse coding is needed. This technique is useful when you have negatively and positively worded questions on a questionnaire and you need to reverse the coding of the likert. Convergent and discriminant validity and common method bias. A confirmatory factor analysis examination of reverse coding. How to perform and report an impactful analysis using. An easy way to reverse code scale items factor analysis. Focusing on exploratory factor analysis an gie yong and sean pearce university of ottawa the following paper discusses exploratory factor analysis and gives an overview of the statistical technique and how it is used in various research designs and applications. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Two reverse coded items items 2 and 4 were removed due to insufficient factor loadings, resulting in. For example, if the possible answers range from 1 to 5, then answer 1 fully disagreeing with a reverse coded statement, is assigned a value of 5, answer 2 is assigned a value of 4, and so on. For example, a questionnaire designed to measure students satisfaction with a course might contain scales on the instructor, content, course workload, and so on. However, a major issue was that the reverse coded items clearly caused problems for 1020% of the raters, who did.
Thiswasdichotomizedat1sdabove the mean because of indications of nonlinearity. A confirmatory factor analysis examination of reverse. A dont know response is coded as a 5 because if it is not known whether the facility is within walking distance, the actual walk is likely more than 31 minutes. Once youve used reliability analysis to identify the items that will produce the most reliable measure, you can use those items to create an average score for your questionnaire, as described below. This concept has been operationalized by a reflective measurement model in past is research using the following items. All items must be reverse coded score on subscale b. Some data sets have items that need to be reverse coded e. I have 21 items that should load onto four factors. Reverse the coding of selected items prior to scale analysis description.
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