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European Journal of Oncology Nursing xxx (2013) 1e6

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European Journal of Oncology Nursing

journal homepage: www.elsevier .com/locate/ejon

Psychometric properties of the Persian version of the Mishel’sUncertainty in Illness Scale in Patients with Cancer

Moosa Sajjadi a,b, Maryam Rassouli a,c,*, Abbas Abbaszadeh d, Hamid Alavi Majd e,Kazem Zendehdel f

aNursing & Midwifery School, Shahid Beheshti University of Medical Sciences, Tehran, IranbGonabad University of Medical Sciences, Gonabad, Iranc Pediatric Nursing Department, Nursing & Midwifery School, Shahid Beheshti University of Medical Sciences, Vali-e Asr Street, Niyayesh Cross, Tehran, IrandDepartment of Nursing, Nursing & Midwifery School, Shahid Beheshti University of Medical Sciences, Tehran, IraneDepartment of Biostatistics, School of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IranfCancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran

Keywords:Uncertainty in illnessMUIS-APsychometricsCancerConfirmatory factor analysis

* Corresponding author. Pediatric Nursing DepartSchool, Shahid Beheshti University of Medical ScienceCross, Tehran, Iran. Tel.: þ98 21 88655372; fax: þ98

E-mail address: Rassouli.m@gmail.com (M. Rassou

1462-3889/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.ejon.2013.09.006

Please cite this article in press as: Sajjadi, M.Patients with Cancer, European Journal of O

a b s t r a c t

Purpose: Uncertainty is a major component in the illness experiences which extraordinarily can affectthe psychological adjustment and the illness outcomes. Uncertainty in illness is defined as inability todefine the illness-related events to the illness or disability in predicting the illness outcomes. The presentstudy aimed to translate the Persian version of Uncertainty in Illness Scale (MUIS-A) and to investigate itspsychometric properties on patients with cancer.Method: In this methodological study, validation of the Persian version of MUIS-A was performed in Iranon 420 cancer patients attending two major hospitals in Tehran, Iran. The scale was translated intoPersian and back translated into English and revised according to editorial comments of the scale de-signers. Then, content and face validity, construct validity, internal consistency reliability and stability ofthe Persian version were measured. Data were analyzed using SPSS version 16 and LISREL 8.5.Results: Mean of the participants MUIS-A score was 90.1 (16.8). Confirmatory factor analysis confirmedvalidity of the whole instrument and its four subscales. The consistency of the instrument with a three-week interval was r ¼ 0.91. Cronbach’s alpha was 0.89 for the whole scale of 32 MUIS-A items anda ¼ 0.58e0.86 for its four factors.Conclusions: The Persian version of the MUIS-A has good psychometric properties. It can be used toassess uncertainty in illness in Iranian patients with cancer.

� 2013 Elsevier Ltd. All rights reserved.

Introduction

Uncertainty is a natural part in the illness experience and canoccur at all stages of disease including diagnosis, treatment andprognosis of the disease. Uncertainty in illness occurs when thepatient is unable to determine the meaning of illness-relatedevents; therefore, it is considered a major cause of psychologicalstress to the patients (Mishel, 1997a, 2013), that can leave majorimpacts on the psychological adaptation and outcomes of the dis-ease (Neville, 2003). Uncertainty in illness is defined as the“inability to determine the meaning of illness-related events when

ment, Nursing & Midwiferys, Vali-e Asr Street, Niyayesh21 88202521.li).

All rights reserved.

, et al., Psychometric propertincology Nursing (2013), http

the patient cannot determine the value of events or cannot accu-rately predict the disease outcome due to the lack of sufficient cues”(Mishel, 1988).

Uncertainty occurs when the individuals cannot form a cogni-tive framework for understanding their status and interpretingillness related events (Bailey et al., 2011; Mishel, 1990, 2013).Therefore, in most cases, it is accepted as a major stressor that mostpeople seek to reduce and to learn methods to cope with (Neville,2003). Chronic diseases are a long term and intense source ofpsychological stress that influences all aspects of patients’ life andreduces their daily activities and quality of life (Flemme et al.,2005). Furthermore, various studies have been conducted onchronic patients such as patients with cardiovascular diseases,dialysis, hepatitis, liver transplantation, AIDS and Alzheimer’swhose results indicate that uncertainty exists in these patients andcan lead to reduction in quality of life and the ability to cope with

es of the Persian version of the Mishel’s Uncertainty in Illness Scale in://dx.doi.org/10.1016/j.ejon.2013.09.006

M. Sajjadi et al. / European Journal of Oncology Nursing xxx (2013) 1e62

illness (Bailey et al., 2009; Brashers et al., 2004; Flemme et al.,2005; Lasker et al., 2010; Madar and Bar-Tal, 2009; Mauro, 2010;Sodowsky, 2012).

Cancer, as one of the chronic diseases, is the second leading causeof death in theWest (Shaha et al., 2008). It is the third cause of deathin Iran after heart diseases and car accidents. Based on the recentstatistics, the rate of cancer incidence in Iran is about 107 people in100,000 people (more than 80,000 people considering Iran’s 75-million population). It is predicted that with regard to the raise ofenvironmental pollution, increasing the elderly (aging community)and population growth, coming decades will witness an increasingtrend in cancer so that it becomes a principle health problem in Iran(Rasaf et al., 2012). Today, advances in cancer diagnosis and treat-ment technology has led to an increase in patients’ survival, and oneof the important points in the care of these patients is to notice andimprove the quality of life (Stewart et al., 2010b).

From the diagnosis time to the onset of treatment, patients withcancer suffer from high levels of emotional tension (Chen et al.,2010). Due to the complexities of treatment and symptoms, pa-tients experience some levels of uncertainty about illness whichoriginates from problems related to the inability to perform dailyactivities, inadequate treatment, and concerns about the relapse ofthe disease (Haisfield-Wolfe et al., 2012). Various studies have beenconducted in the field of uncertainty in illness in different types ofcancer in other countries (mainly Western countries) (Detpraponet al., 2013; Haisfield-Wolfe et al., 2012; Harrow et al., 2008; Kur-ita et al., 2013; Parker et al., 2013; Shaha et al., 2008; Sherman andSimonton, 2010; Stewart et al., 2010a; Woodgate and Degner,2002). The ultimate goal of these studies is to help the patients (ortheir families) to effectively manage uncertainty so that its negativeeffect on the patient’s psychological adaptation is reduced (Stewartet al., 2010b). Nurses are frequently in contact with the patient, thusthey are in the best position to reduce uncertainty in patients byproviding information and promoting patients’ understanding ofhealth (Madar and Bar-Tal, 2009).

Inorder to conduct interventions to reduceuncertainty inpatientswith cancer and to measure effectiveness of these interventions, ascale is needed tomeasure it. There are various scales for uncertaintyassessment in different patients and groups (Lin et al., 2012; Mishel,1997b; Pai et al., 2007; Stewart et al., 2010a). One of the convenientand widely used scales is Mishel Uncertainty in Illness Scale-Adultform (MUIS-A). MUIS-A is a valid and reliable scale and has beenused in several studies. This instrument contains 32 items on Likertscale from 1 (strongly disagree) to 5 (strongly agree) points and oc-curs in four dimensions of ambiguity, complexity, inconsistency, andunpredictability. The instrument scores between 32 and 160, andearning more points shows greater uncertainty (Bailey et al., 2009;Mishel, 1997b). MUIS-A has a good internal consistency with Coro-nbach’s alpha of 0.87 for thewhole instrument, 0.86 for the subscalesof ambiguity (13 items), 0.81 for complexity (7 items), 0.78 forinconsistency (7 items), and 0.65 for unpredictability (5 items). Thisscale has been translated into different languages and its validity andreliability have been studied (Mishel, 1997b).

Despite the importance of the concept of uncertainty in illnessin cancer patients, no valid and reliable tool exists in this regard inIran. Therefore, this study was conducted with the aim of trans-lation and psychometric properties of the Persian Version of“Mishel Uncertainty in Illness Scale” in cancer patients.

Methods

Procedures

The present study is a methodological research (LoBiondo-Wood et al., 2006) through which the MUIS-A scale is translated

Please cite this article in press as: Sajjadi, M., et al., Psychometric propertiPatients with Cancer, European Journal of Oncology Nursing (2013), http

and its Persian version has been validated among patients withcancer. The study populationwas all the cancer patients attendingthe clinics and oncology wards of Imam Khomeini Hospital (Iran’slargest cancer center) and Taleghani Hospital in Tehran. Giventhese centers accept patients from all over the country, results ofthe study can be better generalized to the society. Convenientsampling was performed in order to achieve a sufficient samplesize to conduct a confirmatory factor analysis. The inclusioncriteria were willingness to participate in research, cancer diag-nosis by the oncologist, being aware of one’s illness, being Iranian,the ability to understand and speak Persian, the minimum age of21 years, and absence of other serious illnesses and no history ofserious mental disorders (such as schizophrenia). Type and stageof cancer and treatment typewere not the inclusion criteria of thisstudy. Based on these criteria, eventually 420 individuals werechosen.

Scale translation

In this study, translation and validation of the instrument wasperformed based on the suggested model by Wild et al. (2005).After obtainingwritten permission from the original designer of thescale, the original scale was translated into Persian by two peoplefluent in English and Persian. Then the two translations werecompared and the final version was prepared with a few modifi-cations. Then, the final translated version was given to two peoplefluent in both languages of English and Persian (one native Englishspeaker), who were not in contact with the first people to translateit back into English. Then, the back-translation was contrasted by asupervisor with translations of the original scale in terms of simi-larity of translations, and some minor revisions were made instatements of the Persian version. Afterward, validation process ofthe translated scale was performed by assessing face and contentvalidity, construct validity (using confirmatory factor analysis),reliability, and internal consistency.

Content validity

In order to examine the content validity index (CVI), thetranslated scale was given to ten people (a specialist in clinicalpsychology, an oncologist, two psychiatric nurses, two oncologynursing instructors, four nursing assistant professors withexperience in instrument development) to review that andprovide their correctional comments. They also investigated andaffirmed face validity of the translated scale. Then, the scale wasgiven to 10 patients with cancer to express their idea aboutsimplicity of use, and understandability of words and phrases.The Persian version was finalized without much change in itssentences.

Data collection

To collect the data, after choosing eligible patients andexplaining the study objectives andmethods, the informed consentwas obtained from them. Next, the questionnaire including de-mographics (age, sex, educational level, marital status, occupation,place of residence, type of illness, type of treatment, time of diag-nosis) and MUIS-A scale were given to them to complete.Completion of the questionnaire took about 20e25 min. For illit-erate people, the questionnaire was read and patients’ answersweremarked by the researcher. Investigating validity of theMUIS-Aconstruct and the model fitness was conducted by confirmatoryfactor analysis (CFA) using LISREL statistical software version 8.5.

es of the Persian version of the Mishel’s Uncertainty in Illness Scale in://dx.doi.org/10.1016/j.ejon.2013.09.006

M. Sajjadi et al. / European Journal of Oncology Nursing xxx (2013) 1e6 3

Construct validity

CFA is a structural equationmodeling techniquewhich is used todetermine the goodness of fit between a hypothesized model andthe data obtained from study samples (Kline, 2010). Maximumlikelihood algorithm was used to evaluate the fitness of the model.There are several fit indices for deciding on the goodness of fit ofthe model and it is recommended that different indices be used(Brown, 2006; Seo et al., 2004). In this study, indices of fit chi-square, root mean error of approximation (RMSEA), goodness-of-fit index (GFI), comparative fit index (CFI), adjusted goodness-of-fitindex (AGFI), and standardized root mean square residual (SRMR)were used. One of the most used indexes is chi-square. Because thisindex is related to the sample size, ratio of chi-square to degrees offreedom is used, where values less than 2 indicate a good fit of themodel. Another important index is the RMSEA, where values lessthan 0.08 are acceptable and less than 0.05 indicates good fit of themodel. Researchers are advised to report the confidence interval(Kline, 2010; Seo et al., 2004). Another important index is SRMR,whose acceptable value is 0.06 or less (Brown, 2006; Kline, 2010).Appropriate values are >0.9 for CFI and GFI, and >0.85 AGFI(Bentler, 1990; Helsen et al., 2013).

Reliability

Internal consistency and reliability were measured using SPSSsoftware version 16. Scale internal consistency was measured byCronbach’s alpha for the total scale and each subscale separately.

Table 1Demographic and clinical characteristics of patients with cancer (n ¼ 420).

Age (year)Time since diagnosis (months)

Sex FemaleMale

Marital status SingleMarriedWidowed or divorced

Education level IlliteratePrimary and Guidance schDiplomaUniversity degree

Occupation Self-employedEmployeeHousewifeUnemployedOther

Time since diagnosis (months) <66e24>24

Type of cancer BreastColon and rectumGastric/esophagusHematologicUterus/ovarianProstateLungSkinOther

Metastasis YesNo

Kind of treatment ChemotherapyChemotherapy and surgerChemo and radiotherapyAll of themOther

Please cite this article in press as: Sajjadi, M., et al., Psychometric propertiPatients with Cancer, European Journal of Oncology Nursing (2013), http

The best method used to evaluate the internal consistency isCronbach’s alpha (Polit and Beck, 2013). The Cronbach’s alpha ofabout 0.7 is sufficient, and of >0.80 indicates high internal con-sistency of the tool (Polit and Beck, 2013). The reliability wasmeasured by Pearson’s or Spearman’s correlation coefficients intesteretest on 15 patients with a three-week interval. Usually, thetime interval of 2e3 weeks is appropriate between two tests(Hawthorne et al., 2011; Polit and Beck, 2013).

Results

A total of 420 questionnaires were analyzed. Demographiccharacteristics of the study sample are shown in Table 1. Contentvalidity index was measured on relevance, clarity, and simplicity ofthe translated scale as 0.98, 0.95, and 0.96, respectively.

Table 2 showsmean and standard deviation of the overall scoresof MUIS-A and its dimensions. In order to have a better comparisonbetween the present scale and the original one, data of the presentstudy were compared to the combined multiple studies on patientswith cancer (Mishel, 1997b). The results show that mean of theoverall score of uncertainty in illness in the present study (90.1) isgreater than that of the combined sample of cancer patients pro-posed byMishel (79.5). Coefficient of Cronbach’s alpha was 0.89 forthe overall scale, and 0.58e0.86 for its dimensions (Table 2). Thecorrelation coefficient testeretest reliability for MUIS-A was 0.91(p < 0.001). Correlation coefficients for subscales of ambiguity,complexity, inconsistency, and unpredictability were respectively0.90, 0.74, 0.83, and 0.60.

Mean SD (range)

46.4 13.9 (21e79)18.5 24.2 (3e168)

N %

217 51.7203 48.358 13.8331 78.831 7.387 20.7

ool 151 36107 25.575 17.976 18.134 8.1174 41.435 8.3103 24.1166 39.5163 38.891 21.7103 24.599 23.636 8.672 17.125 65 1.221 55 1.254 12.9143 36.3251 63.7105 25

y 189 4526 6.290 21.410 2.4

es of the Persian version of the Mishel’s Uncertainty in Illness Scale in://dx.doi.org/10.1016/j.ejon.2013.09.006

Table 2Scores for MUIS-A scale and its dimensions in Iranian patients with cancer and it’s comparison with Mishel’s data bank.

Ambiguitymean (SD) e a

Complexitymean (SD) e a

Inconsistencymean (SD) e a

Unpredictabilitymean (SD) e a

Total mean (SD) e a

Iranian patientswith cancer (N ¼ 420)

41.8 (9.4)e0.86 15.1 (3.2)e0.58 18.8 (4.2)e0.71 14.4 (3.5)e0.65 90.1 (16.8)e0.89

Mishel’s combined datafor cancer patients (N ¼ 761)

32.3 (9.3)e0.87 16.5 (5)e0.80 14.9 (4.7)e0.80 15.8 (3.7)e0.67 79.5 (16.9)e0.90

M. Sajjadi et al. / European Journal of Oncology Nursing xxx (2013) 1e64

Construct validity

To investigate construct validity and provide the most appro-priatemodel for theMUIS-A, confirmatory factor analysis was used.To this end, full samples of cases were randomly split into twoapproximately equal groups. 200 subjects were considered ascalibration sample and 220 subjects were considered as evaluationsample. Calibration samples were used to check the models (2 and4 factors) and do possible revisions. Evaluation sample was used tovalidate the appropriate model. Two-dimensional model of thescale did not have good fit indices, but the four-dimensional modelhad better fit indices. The chi-square, RMSEA, SRMR and AGFIindices confirm the fit indices of the model (Table 3). By assessingthe scale items, it was determined that the item 32 “The serious-ness of my illness has been determined” had a weak item-scalecorrelation coefficient (r ¼ 0.02), therefore, item 32 was removed.According to the suggestion of modification of fit indices inconfirmatory factor analysis, transferring item 8 “I do not knowwhen to expect things will be done to me” (from the ambiguity tothe inconsistency) and item 28 “treatment which is being done tome has a known probability of success” (from the complexity to theunpredictability) improved the fit of the model. Therefore, the four-dimensional model of MUIS-A with 31 items (ambiguity 12 items,complexity 5 items, inconsistency 8 items and unpredictability 6items) is a model with the best fit indices. CFI and GFI indices areacceptable (Bentler, 1990) and other indices such as the ratio of chi-square to degree of freedom, RMSEA, AGFI and SRMR indicate agood fit of the model (Brown, 2006; Helsen et al., 2013; Kline,2010).

In order to further investigate validity of the construct, therelationship between education level and uncertainty in illness ratewas used. In this study, a strong inverse correlation was foundbetween uncertainty and the level of education (r ¼ �0.47,p < 0.001) in the sense that patients with higher level of educationhad less uncertainty.

Discussion

Uncertainty in illness is a concept that can have broad impact oncancer patients and its investigation in this group of patients is of

Table 3Confirmatory Factor analysis Fit indices for the different MUIS-A version in Iranian patie

c2 (df), p RMSEAc (

MUIS-A, 2 factorsa 657.4 (349), p < 0.001 0.067 (0.0MUIS-A, 4 factorsa (original) 767.4 (458), p < 0.001 0.054 (0.0MUIS-A, 4 factorsa (modified) 660.7 (428), p < 0.001 0.047 (0.0MUIS-A, 4 factorsb (modified) 652.3 (428), p < 0.001 0.049 (0.0

a Calibration sample (N ¼ 200).b Validation sample (n ¼ 220).c Root mean error of approximation.d Comparative fit index.e Goodness-of-fit index.g Standardized root mean square residual.f Adjusted goodness-of-fit index.

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great importance. Despite the importance of the issue, this problemhas not been studied in Iran that can be attributed to lack of propertools in Iran. Therefore, this study was conducted with the aim oftranslating and validating the Persian version of the uncertainty inillness scale in patients with cancer. In this study, the MUIS-A scalewas translated into Persian and its psychometric properties andfactor structurewere evaluated.When a tool is translated or used inanother culture or society, it is essential to evaluate its psycho-metric properties because that may not be appropriate in the newsociety (Hillen et al., 2013; Michaeli Manee, 2011). In this study,content validity, construct validity, and reliability of this tool wereassessed.

Based on the findings, the Persian version of MUIS-A generallyhas good reliability and validity and its dimensions’ construct issimilar to that of the original one (Mishel, 1997b). In this study, ithas been shown that with regard to content validity index of 0.96,the Persian version of MUIS-A has a good content validity. Polit andBeck (2013) suggest that the CVI value of 0.9 or more should beconsidered as a standard for content validity of the scales (Polit andBeck, 2013).

Confirmatory factor analysis of MUIS-A was conducted using asample of 420 cancer patients. Goodness-of-fit indices indicatedthat the original model (32-item and 4-dimensional) of Persianversion of the uncertainty in illness scale is appropriate, but forbetter fit indices and to enhance the fit indices some changes areneeded to be made in the original scale. In confirmatory factoranalysis, some suggestions are given by Lisrel to modify andimprove the model fit indices. If they are justifiable logically andtheoretically, they can be applied (Kline, 2010). In the Persianversion, item 32 “The seriousness of my illness has been deter-mined” from complexity dimension was deleted due to its lowcorrelation coefficient of item-scale.

In validation of the Swedish version of this scale for the cardiacpatients, it was indicated that this item has no significant corre-lation with the overall score of the scale and complexity subscale.Furthermore, items 10 and 22 were excluded from the Swedishversion (Hallberg and Erlandsson, 1991). Another study was con-ducted in Iran to validate the scale of uncertainty in illness e

family form. This scale assesses uncertainty from patients’ family’sperspective. The original version of this scale has 31 items and is

nts with cancer.

90% CI) CFId GFIe AGFIf SRMRg

59e0.074) 0.76 0.81 0.78 0.07148e0.060) 0.87 0.90 0.88 0.06340e0.054) 0.91 0.92 0.90 0.04844e0.054) 0.91 0.93 0.91 0.046

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M. Sajjadi et al. / European Journal of Oncology Nursing xxx (2013) 1e6 5

one-dimensional. In psychometric properties of this scale appliedfor 310 family members of patients hospitalized in the ICU, it wasshown that 5 items were not appropriate and had to be removed.Content and convergent validity and reliability of the Persianversion of the scale was confirmed in the form of a 26-item scale.However, in this study, construct validity and subscales of this toolwere not assessed by factor analysis (Vagharseyyedin and Vanaki,2011). Another study was performed by Pai et al. (2007) on thepsychometrics of the uncertainty scale in pediatric patients(CUIS). This scale is the adjusted form of Mishel’s Uncertainty inIllness Scale-Community Form (MUIS-C). By conducting a sepa-rate exploratory and confirmatory factor analysis on 373 childrenwith chronic illnesses, 8 items were removed from 23 items of theoriginal instrument. The new scale with 14 items and two di-mensions received very good fit for this group of patients.Removing item 8 “I know everything about my disease” was rec-ommended by the CFA, which logically would be acceptablebecause children could not understand everything about theirillness (Pai et al., 2007). Nevertheless, in our opinion, its low item-total correlation coefficient in the Persian version seems to bemore related to the sample of the study because all subjects, ac-cording to the inclusion criteria, were aware of their cancer, soalmost all of them had agreeably answered this question. Thisprobably would be a good item for the patients in the process ofcancer diagnosis.

In the Persian version, item 8 of the ambiguity dimension “I donot know when to expect things will be done to me” was trans-ferred to the inconsistency dimension. Furthermore, item 28“treatment which is being done to me has a known probability ofsuccess” was transferred from the complexity dimension to theunpredictability dimension.

Factor structure in the original scale was shown changeable inanalyses conducted by Mishel at different times, in the sense thatsome items were transferred from one factor to another (Mishel,1997b). Findings obtained by Pai et al. (2007) showed that in thevalidated scale of uncertainty in pediatric patients, some items ofthe original scale can be placed within another factor (Pai et al.,2007).

In another study that conducted the psychometric properties ofthis scale for patients with brain tumors, some items of complexityand ambiguity were transferred to other factors (Lin et al., 2012).Other studies also have been conducted on the validation of thesame scale whose findings showed that the scale items can betransferred from one factor to the next (Helsen et al., 2013; Hillenet al., 2013).

Transfer of these items theoretically and logically has noobstacle and Mishel herself has integrated some of them in thetwo dimensional MUIS scale. Another reason may be that Iranianpatients are not able to differentiate among sense of ambiguity,complexity, and unpredictability. Therefore, it is proposed aqualitative research be conducted to infer the sense of uncer-tainty and its dimensions among the Iranian patients withcancer.

According to the theory of uncertainty in illness, a negative andsignificant relationship should be between the education level andscore of uncertainty in illness, which has been confirmed in manystudies (Mishel, 2013). In this study, a strong and inverse rela-tionship was found between education level and uncertainty inillness so as education level increases in them, the level of uncer-tainty decreases. Furthermore, this finding confirms the constructvalidity of this scale.

Findings of the present study show that mean and standarddeviation of the scores of uncertainty in illness scale and its di-mensions are very similar to its values in the combined sample ofthe patients with cancer investigated by Mishel (Mishel, 1997b).

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This issue itself also can be an approval of the Persian versionvalidity of this scale and its dimensions. The score of uncertainty inillness in our study was higher. This finding can be justified bylower level of patients’ education and knowledge in our society.

The results of the present study showed that the Persian scale ofMUIS-A has a good internal consistency. In the present study, theoverall Cronbach’s alpha of this scale and its dimensions is close tothe obtained values in the combined sample of cancer patients,conducted using the original scale. Two dimensions of the scalehave an acceptable internal consistency. Lower alpha in some di-mensions is because of its low number of items. For example, therelatively low Cronbach’s alpha in complexity dimension (0.58) canbe attributed to the fact that 7 items in the original scale reduced to5 items in the Persian version. Nevertheless, the obtained alpha forvarious aspects of this study is close to that in some studies re-ported by Mishel (Mishel, 1997b). The ambiguity dimension, withregard to its high internal consistency and its high correlation withthe whole scale (p < 0.001, r ¼ 0.93), can be used alone, but it isbetter to use the whole instrument in the study. In addition to theinternal consistency, results of the testeretest showed that thePersian version of this scale has a good stability.

Limitations

The present study had some limitations. First, about 21% of thesamples were illiterate, and we had to complete the questionnairethrough interviews, which was one of the limitations of thisresearch. Second, it should also be noted that applying the modi-fication indices to guide CFA analysis increases the probability ofthe findings being influenced by chance.

Conclusion

In sum, the results of the present study show that the Persianscale of uncertainty in illness is a scale that not only has a goodvalidity and reliability but also its four-dimensional structure isconfirmed. Therefore, it is applicable to assess uncertainty in illnessin Iranian patients with cancer. Use of this scale by nurses and re-searchers can help to promote nurses’ knowledge and holistic careand ultimately help to improve patient care. This study will be acornerstone for the future studies in the area of uncertainty inillness in other groups of patients in Iran. Regarding the cognitivesense of uncertainty in illness, qualitative studies are needed toknow its other possible dimensions in Iranian patients.

Conflict of interest

The authors declare no conflicts of interest.

Acknowledgment

The present study is a research project adopted by ShahidBeheshti University of Medical Sciences (Tehran e Iran) and a partof a nursing doctoral thesis. Hereby, we express our appreciation toShahid Beheshti Nursing and Midwifery School officials, and alsoauthorities and staff in wards and Iran Cancer Center of ImamKhomeini Hospital and Tehran Taleghani Hospital. Finally, weparticularly thank all the participants.

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