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Injection Drug User Quality of Life Scale (IDUQOL): Findings from a content validation study Hubley, Anita M; Palepu, Anita Jul 30, 2007

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ralHealth and Quality of Life OutcomesssBioMed CentOpen AcceResearchInjection Drug User Quality of Life Scale (IDUQOL): Findings from a content validation studyAnita M Hubley*1 and Anita Palepu2,3Address: 1Measurement, Evaluation, and Research Methodology, Department of Educational and Counselling Psychology, and Special Education, University of British Columbia, Vancouver, BC, Canada, 2Division of Internal Medicine, Department of Medicine, University of British Columbia, Vancouver, BC, Canada and 3Department of Medicine, St. Paul's Hospital, Vancouver, BC, CanadaEmail: Anita M Hubley* - anita.hubley@ubc.ca; Anita Palepu - anita@hivnet.ubc.ca* Corresponding author    AbstractBackground: Quality of life studies among injection drug users have primarily focused on health-related measures. The chaotic life-style of many injection drug users (IDUs), however, extends farbeyond their health, and impacts upon social relationships, employment opportunities, housing, andday to day survival. Most current quality of life instruments do not capture the realities of peopleliving with addictions. The Injection Drug Users' Quality of Life Scale (IDUQOL) was developed toreflect the life areas of relevance to IDUs. The present study examined the content validity of theIDUQOL using judgmental methods based on subject matter experts' (SMEs) ratings of variouselements of this measure (e.g., appropriateness of life areas or items, names and descriptions of lifeareas, instructions for administration and scoring).Methods: Six SMEs were provided with a copy of the IDUQOL and its administration and scoringmanual and a detailed content validation questionnaire. Two commonly used judgmental measuresof inter-rater agreement, the Content Validity Index (CVI) and the Average Deviation Mean Index(ADM), were used to evaluate SMEs' agreement on ratings of IDUQOL elements.Results: A total of 75 elements of the IDUQOL were examined. The CVI results showed that allelements were endorsed by the required number of SMEs or more. The ADM results showed thatacceptable agreement (i.e., practical significance) was obtained for all elements but statisticallysignificant agreement was missed for nine elements. For these elements, SMEs' feedback wasexamined for ways to improve the elements. Open-ended feedback also provided suggestions forother revisions to the IDUQOL.Conclusion: The results of the study provided strong evidence in support of the content validityof the IDUQOL and direction for the revision of some IDUQOL elements.BackgroundIn the health and medical fields, quality of life (QoL) isrelated quality of life (HRQOL) or the functional effects ofrespondents' perceived mental and physical health [3].Published: 30 July 2007Health and Quality of Life Outcomes 2007, 5:46 doi:10.1186/1477-7525-5-46Received: 13 March 2007Accepted: 30 July 2007This article is available from: http://www.hqlo.com/content/5/1/46© 2007 Hubley and Palepu; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Page 1 of 13(page number not for citation purposes)widely used to evaluate social and clinical interventions,treatment side effects, and disease impact over time [1,2].Most of these QoL instruments tend to focus on health-Gill and Feinstein [3], however, defined QoL as a reflec-tion of respondents' perceptions and reactions to not onlytheir mental and physical health, but also to non-healthHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46related aspects of their lives (e.g., family, friends, work).Thus, measurement of QoL needs to encompass morethan just the health-related aspects of respondents' lives.Nearly all studies of QoL in injection drugs users (IDUs)use measures of HRQOL [4-8]. Commonly used measuresof HRQOL with this population include the Opiate Treat-ment Index [9], Nottingham Health Profile [10,11], theBerlin Quality of Life Profile [12] and the MOS surveys(including the SF-36 and the SF-12) [13-16]. Many studieshave shown that IDUs experience significantly lowerHRQOL relative to the general population [16-20] but, asnoted by Fernández Miranda [21], remarkably little pub-lished research has examined QoL as an outcome variablein the treatment of drug addiction [22,23].Although previous research with IDUs and related popu-lations (e.g., illicit drug users, HIV/AIDS) has consideredthe effects of non-health related aspects of respondents'lives on their HRQOL [4,7,15,24-28] or even on the initi-ation or maintenance of drug use [29-35], rarely has pub-lished research with IDUs used a broadly-defined QoLmeasure (i.e., one that captures various social, psycholog-ical, physical, geographic, and occupational domains ofQoL). Two exceptions would be Wasserman and col-leagues [36], who examined the psychometric propertiesof Lehman's [37] Quality of Life Interview – Brief Versionwith IDUs, and Dunaj and Kovác [38], who comparedconvicted drug addicts and controls on broadly-definedQoL using the WHOQOL-BREF [39] and ComQol-A5[40]. Dunaj and Kovác reported that addicts scored signif-icantly lower than controls in their subjective ratings ofareas such as health, emotional well-being, safety, andsocial standing.Although broader measures of QoL are beginning to beused with IDUs [36,38] and are certainly an improvementover the use of strictly HRQOL measures, measures devel-oped specifically for the IDU population and using a con-text sensitive approach that considers the many life areasdeemed by IDUs as critical to their QoL, are still needed.QoL, as defined by the World Health Organization Qual-ity of Life (WHO-QOL) group, refers to "an individual'sperceptions of their position in life in the context of theculture and value systems in which they live, and in rela-tion to their goals, expectations, standards, and concerns"(pp. 1–2) [41]. The item content and methods of admin-istration for most available QoL instruments do not meas-ure the QoL of drug users in a culturally-sensitive fashion[42]. IDUs live in a distinct environment characterized bya high prevalence of infectious disease, crime, violence,and lack of stable housing. Many IDUs cannot depend onbasic necessities and experience considerable instability inA recently developed broadly-defined QoL measure, theInjection Drug User Quality of Life (IDUQOL) scale, wasdesigned to capture the health and non-health relatedaspects of IDUs' lives that would be important compo-nents of their quality of life, particularly given their indi-vidual circumstances and environment [43,44]. Thismeasure has also been adapted for use in Spanish withinjection and non-injection drug users [45]. To use aninstrument with confidence, it is important that there beevidence of validity – that is, the meaningfulness, useful-ness, and appropriateness of an instrument for a givenpopulation in a given context [46-48]. Previous researchhas examined the factor structure, internal consistency,and test-retest reliability of scores from the IDUQOL aswell as the criterion-related, convergent, and discriminantvalidity of inferences made from the measure [44]. Con-tent validity, a critical step in the test development andvalidation process [49-51], refers to the degree to whichelements of an assessment tool are representative of theconstruct of interest and appropriate for a given popula-tion [52]. Importantly, the elements of interest in a con-tent validation study are not just the content or items ofthe measure, but all elements of the instrument includingthe instructions, response format, and scoring procedures[53].The purpose of the present study was to examine the con-tent validity of the IDUQOL using judgmental methodsbased on subject matter experts' (SMEs) ratings of theIDUQOL title, items, instructions, response format, scor-ing procedures, and record form.MethodsParticipantsThe sample consisted of a panel of six subject matterexperts (SMEs; 50% male), all of whom were researchersworking in the area of drug use in the United States orCanada with an average of 10 years experience in the field.Two SMEs were epidemiologists and four SMEs were phy-sicians who also provided addiction and medical care todrug users in their clinical practice. As noted by others[54], there is no set number of SMEs required for contentvalidation studies. Typically, somewhere between three toten experts is recommended, although a minimum of fiveSMEs is recommended to control for chance agreement;furthermore, the larger the number of experts, the greaterthe confidence in the ratings and the easier it is to detectrater outliers [53,55].MeasuresThe subject matter experts were provided with a copy ofthe IDUQOL and its administration and scoring manualand a detailed content validation questionnaire. EthicsPage 2 of 13(page number not for citation purposes)many aspects of their lives. approval for this study was obtained from the UniversityHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46of British Columbia and Providence Health Care ResearchEthics Boards.Injection Drug User Quality of Life Scale (IDUQOL)The original IDUQOL, which includes both health andnon-health related aspects of QoL [3] and is based on theWHO-QOL group definition of QoL [41], consisted of 20life areas. Several of these areas (e.g., Drugs, Drug Treat-ment, Harm Reduction and Neighbourhood Safety) wereincluded in the measure precisely because of their partic-ular relevance to the social and physical reality of IDUs asconfirmed by focus groups during the development phase[43]. Each IDUQOL life area is represented on a 4 by 4inch card, with the name of the area printed on the frontalong with a simple picture. A description of the life areais presented on the back (see Table 1 for a list of all 20 lifeareas and descriptions). Graphic representation of the lifeareas is intended to make the instrument more accessibleto individuals who have low literacy skills or do not speakEnglish as a first language. When administering the IDU-QOL, the interviewer starts by showing the respondenteach of the 20 life area cards and describes the area. Theparticipant selects those areas that he/she deems impor-tant to his/her quality of life and any remaining cards areset aside. The cards representing important areas are laidout and the participant is given three poker chips for eachcard. The total number of chips can, therefore, range from0 (no life areas are important) to 60 (all 20 life areas areimportant). The participant then distributes the chipsacross the cards to indicate the level of importance of eachlife area, with more chips indicating greater importance.Next, the participant provides a satisfaction rating for eacharea, using a 6-point Likert-type scale anchored by 1 (verydissatisfied) and 6 (very satisfied) and illustrated with sixstylised frowning and smiling faces.When scoring the IDUQOL, the importance rating(number of chips) of each area is divided by the totalnumber of chips used by that participant and then multi-plied by the satisfaction rating for that area. This producesan area score. Finally, all area scores are summed to obtainan overall quality of life score ranging from 1 (very dissat-isfied) to 6 (very satisfied).IDUQOL content validation questionnaireThe questionnaire was divided into seven sections cover-ing the clarity of the instrument title, ease of administra-tion procedure instructions, clarity of the names anddescriptions of the 20 IDUQOL life areas, whether each ofthe 20 IDUQOL life areas should be included in the meas-ure (including whether any life areas need to be added,revised, or deleted), ease of the response formats used foreach of importance and satisfaction ratings, clarity of scor-provide open-ended commentary in each section. As rec-ommended by Lynn [55], a four-point Likert type scalewas used in most cases. For questions involving clarity,the following four response options were used: 0 = not atall clear, 1 = somewhat clear, 2 = mostly clear, 3 = veryclear. For questions involving ease, the following fourresponse options were used: 0 = not at all easy to follow/use, 1 = somewhat easy to follow/use, 2 = mostly easy tofollow/use, 3 = very easy to follow/use. For questionsinvolving inclusion of items, the following three responseoptions were used: 0 = no, 1 = unsure, 2 = yes. Two ques-tions asked about how helpful the provided exampleswere in the manual; for these, the following four responseoptions were used: 0 = not at all helpful, 1 = somewhathelpful, 2 = mostly helpful, 3 = very helpful.ProceduresThe six SMEs were identified through the second author'sprofessional contacts with nationally and internationallyrecognized experts in the area of substance abuse epidemi-ology and treatment. They were sent a letter of invitationand agreed to take part in the study. None of the SMEswere associated with the development of the IDUQOL.The SMEs were mailed a copy of the IDUQOL (whichincluded the 20 life area cards, poker chips, satisfactionrating card, and record form), the administration andscoring manual, and the IDUQOL content validationquestionnaire. As suggested by Grant and Davis [56],SMEs were provided with the conceptual basis for theIDUQOL via the brief introduction in the manual inwhich the definition of QoL underlying this measure, thetarget population, and how the measure is intended to beused was provided. The SMEs completed the content vali-dation questionnaire at their leisure and independently ofone another. All SMEs returned usable questionnaires.Two commonly used judgmental measures of inter-rateragreement, the Content Validity Index (CVI) [55,57] andthe Average Deviation Mean Index (ADM) [58-60], wereused to evaluate SMEs' agreement on ratings of the variousIDUQOL elements. The two measures provide very differ-ent types of information, however, and should be viewedas complementary. Generally, the CVI indicates the pro-portion of SMEs that endorse an element as content validwhereas the ADM indicates the degree of disagreementamong SMEs in the response option selected regardless ofwhether they, as a group, endorsed an element or not.Thus, one should first examine the CVI values to deter-mine whether the SMEs endorsed an item or not and thenconsider the level of agreement among the SMEs by exam-ining the ADM.The CVI can be computed at the individual item level (I-Page 3 of 13(page number not for citation purposes)ing procedure instructions, and the ease of use of therecord form. Experts were also given the opportunity toCVI) and at the level of the overall scale or subscale (S-CVI). I-CVI is computed as the proportion of SMEs thatHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46endorse an item. Following standard procedures for fourresponse options [49,55], ratings of 2 or 3 were combinedand treated as endorsements by SMEs whereas ratings of 0or 1 were combined and treated as non-endorsements inthe present study. When three response options wereused, a rating of 2 was treated as an endorsement by SMEswhereas ratings of 0 or 1 were combined and treated asnon-endorsements. A minimum of five out of the sixSMEs (I-CVI ≥ .83) had to endorse an item to achieve sig-nificant evidence (α = .05) of content validity for anygiven item on the IDUQOL content validity questionnaireand to provide confidence that agreement was not occur-ring by chance alone [55]. Elements that were notendorsed by a minimum of five SMEs were examined fur-ther to determine if appropriate revisions could be made.The S-CVI may be defined and computed a number of dif-ferent ways, but Polit and Beck [49] recommend using theaverage proportion of items endorsed by the SMEs (whatthey refer to as S-CVI/Ave) and computing this as the aver-age of the I-CVI values. This is the approach that will bejudged content valid" (p. 384). For S-CVI/Ave, the mini-mum acceptable value is recommended to be .90 [49].The ADM Index measures dispersion of ratings about themean rating; thus, it is actually a measure of disagreementso lower values indicate higher levels of agreement amongSMEs. An advantage of the ADM Index is that it provides ameasure of dispersion that is directly interpretable interms of the original rating scale units. The general cut-offfor determining acceptable ADM values is based on c/6,with c referring to the number of response options [59].Thus, using this guideline for practical significance,acceptable ADM values are .50 or less for ratings with threeresponse options and .69 or less for ratings with fourresponse options. Critical values that can be used to eval-uate whether an obtained ADM could have been achievedby chance can also be computed. Critical values for ADMat the 5% level of significance, taking into account thenumber of SMEs and the number of response options inthe present study, would be .28 or less for three responseoptions and .44 or less for four response options [58].Table 1: Injection Drug User Quality of Life (IDUQOL) life area names and descriptionsLife Area DescriptionBeing Useful e.g., volunteering, employment, participating in the community, helping othersCommunity Resources e.g., food bank, soup kitchen, shelters, outreach programs, social service agenciesDrugs drug use – e.g., alcohol, heroin, cocaine, crackDrug Treatment e.g., detox, recovery house, residential treatment, methadone, abstinenceEducation e.g., formal schooling, literacy programsFamily e.g., parents, children, siblings, foster families (not friends)Feeling Good about Yourself e.g., self-esteem, self-worthFriends anyone you consider a friend (but not family)Harm Reduction access to, and experience with: e.g., methadone treatment, needle exchange, safe injection programs, prescription heroinHealth mental and physical health, including HIV, AIDS, Hepatitis C, disability, schizophreniaHealth Care access to, and experience with: physicians, nurses, hospitals, clinics, ERHousing e.g., owning, renting, house, apartment, hotel room, shelters, homelessIndependence and Free Choice e.g., making your own decisions, autonomy, being able to do things on your own, having individual rightsLeisure Activities e.g., music, sports, movies, books, partiesMoney e.g., income, welfare, cash flow, meeting your needsNeighborhood Safety e.g., crime, violence, police harassmentPartner(s) e.g., spouse, common-law partner, same-sex partner, girlfriend or boyfriend (not casual partners)Sex e.g., sexual intimacy, quantity or quality of sex, sex in exchange for money or drugs, sexual abuseSpirituality e.g., religion, faith, belief in a higher being or spiritual world (or not)Transportation e.g., car, taxi, public transportation, getting to places you need to goPage 4 of 13(page number not for citation purposes)used in the present study in conjunction with Lynn's [55]description of S-CVI as "the proportion of total itemsADM values that are equal to or below these critical valuesare unlikely to have been obtained by chance. ElementsHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46for which ADM values were neither practically nor statisti-cally significant or were only practically significant wereexamined further to determine if appropriate revisionscould be made.ResultsContent validity evidence for IDUQOL life areasTable 2 presents the I-CVI and ADM results for each of the20 IDUQOL life areas indicating whether (a) each life areawas appropriate for a QoL measure for IDUs, (b) thename of the life area was clear, and (c) the description ofthe life area was clear. I-CVI results showed that all indi-vidual life areas, including the name used and the descrip-tion provided, were endorsed by a minimum of five SMEs.The ADM results provide additional information about theextent to which the SMEs agreed on the exact rating (e.g.,not at all clear, somewhat clear, mostly clear, very clear)for each life area. In all cases, acceptable agreement (i.e.,practical significance) was obtained. In terms of theappropriateness of the life areas, each life area alsoshowed statistically significant agreement among theSMEs. When considering whether the name of the life areawas clear, there were only two cases (i.e., Drugs, Inde-pendence & Free Choice) in which agreement was accept-able, but not statistically significant – meaning thatagreement could have occurred by chance. In the case ofDrugs, five SMEs rated this name as 'very clear' whereasone SME thought it was only 'somewhat clear' becausedrugs could be confused with medications. Independence& Free Choice was rated as 'mostly clear' by half of theSMEs and 'very clear' by the other half of SMEs with theproblem being different interpretations of the word "inde-pendence". When considering whether the description ofthe life area was clear, there were three cases (i.e., BeingUseful, Drugs, Feeling Good about Yourself) in whichagreement was acceptable, but not statistically significant.The description for Being Useful was rated as 'somewhatclear' by one SME, 'mostly clear' by one SME and 'veryclear' by four SMEs. Most SME comments were focused onthe visual depiction provided on the card and no sugges-tions for changes or additions to the description wereoffered. The description for Drugs (i.e., "drug use – e.g.,alcohol, heroin, cocaine, crack") was rated as 'somewhatclear' by one SME, 'mostly clear' by two SMEs and 'veryclear' by three SMEs. There were two concerns raised bySMEs. The first and most prominent concern was that welimited this life area to use of drugs; the second concernwas that we only listed four drugs. The description forFeeling Good about Yourself (i.e., "e.g., self-esteem, self-worth") was rated as 'mostly clear' by half of the SMEs and'very clear' by the other half of the SMEs. No suggestionswere made for changes to the description.SMEs were also asked if there were any life areas that theywould recommend deleting or adding to the IDUQOL.No life areas were recommended for deletion from theIDUQOL. The following additional life areas were sug-gested: food, pets, personal safety, sense of future (e.g.,hopefulness, aspirations), employment (as its own lifearea separate from Being Useful), and pain.Table 3 shows that the S-CVI/Ave for the element group-ings of Appropriateness, Name clarity, and Descriptionclarity of the IDUQOL life areas ranged from .97 to .99,which exceeded the minimum value of .90 and is alsostrong evidence of content validity.Content validity evidence for other IDUQOL elementsTable 3 also shows that the S-CVI/Ave for the elementgroupings of Clarity of Title and Target Population, Easeof Administration Procedure, Ease of Scoring Procedure,and Helpfulness of Provided Examples ranged from .92 to1.00. Only Ease of Response Formats produced a S-CVI/Ave (.83) that was below the minimum recommendedvalue of .90, although both items were endorsed by fiveout of six SMEs.I-CVI and ADM results for other individual elements (e.g.,title, administration instructions, scoring instructions,record form) of the IDUQOL measure and manual arepresented in Table 4. I-CVI results showed that all individ-ual elements were endorsed by a minimum of five SMEs.The ADM results show that acceptable agreement (i.e.,practical significance) was obtained in all cases, althoughthere were four cases in which agreement was not statisti-cally significant (i.e., Clarity of Title, Response Format –Chips, Response Format – Smiley Faces, Scoring Proce-dure – Summed Score).The name or title of the IDUQOL was rated as 'somewhatclear' by one SME, 'mostly clear' by one SME and 'veryclear' by four SMEs, with no suggestions made for how tomake the title clearer. The Response Format – Chips wasrated as 'somewhat easy to use' by one SME, 'mostly easyto use' by one SME, and 'very easy to use' by four SMEs.Suggestions were made for simplifying the instructionsgiven to IDUs about how to use the poker chips to indi-cate the importance of the different life areas. In addition,it was suggested that poker chips might act as a trigger forIDUs with gambling issues. The Response Format – Smi-ley Faces was rated as 'somewhat easy to use' by one SMEand 'very easy to use' by five SMEs. It was suggested thatwe consider using an odd-numbered Likert-type scale(rather than our 6-point Likert-type scale) for the smileyfaces that would permit a neutral response. The ScoringProcedure – Summed Score was rated as 'somewhat easyPage 5 of 13(page number not for citation purposes)to follow' by one SME, 'mostly easy to follow' by one SME,and 'very easy to follow' by four SMEs. It was suggestedHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46that we clarify the headings on the record form so theywould better match the terms used in the manual.Suggested revisions to the IDUQOL based on SME feedbackOpen-ended feedback and comments from the SMEsresulted in several other suggestions for changes to theIDUQOL measure, materials, and manual. These may begrouped into three points. First, suggestions were made toexpand the descriptions for (a) Education, (b) Family, and(c) Sex. Second, it was pointed out that we needed to showgreater diversity in our cards involving people – specifi-cally Family and Friends. Third, we were advised to revisethe cards depicting (a) Being Useful, and (b) Independ-ence and Free Choice to make them clearer.DiscussionTest development and validation are ongoing processesdesigned to ensure measures and the inferences madefrom them remain appropriate, relevant, and useful forTable 2: Item level CVI (I-CVI) and ADM index values for each of the 20 IDUQOL life areasAppropriate?a Nameb DescriptionbLife Area I-CVI ADM I-CVI ADM I-CVI ADMBeing Useful 1.00 .00 1.00 .44 0.83 .67Community Resources1.00 .00 1.00 .28 1.00 .28Drugs 1.00 .00 0.83 .55 0.83 .67Drug Treatment 0.83 .28 1.00 .00 1.00 .28Education 0.83 .28 1.00 .00 1.00 .28Family 1.00 .00 1.00 .00 1.00 .44Feeling Good about Yourself0.83 .28 1.00 .28 1.00 .50Friends 1.00 .00 1.00 .00 1.00 .28Harm Reduction 1.00 .00 1.00 .00 0.83 .33Health 1.00 .00 1.00 .00 1.00 .28Health Care 1.00 .00 1.00 .00 1.00 .28Housing 1.00 .00 1.00 .00 1.00 .00Independence and Free Choice0.83 .28 1.00 .50 1.00 .00Leisure Activities 1.00 .00 1.00 .00 1.00 .00Money 1.00 .00 1.00 .00 1.00 .28Neighborhood Safety1.00 .00 1.00 .00 1.00 .44Partner(s) 1.00 .00 1.00 .28 1.00 .00Sex 1.00 .00 1.00 .00 1.00 .44Spirituality 1.00 .00 1.00 .00 1.00 .00Transportation 1.00 .00 1.00 .00 1.00 .00a Ratings were made on a 3-point scale. b Ratings were made on a 4-point scale.Note. I-CVI: 1.00 = endorsement by all six subject matter experts (SMEs); 0.83 = endorsement by five of six SMEs. ADM Index: with a 3-point scale, acceptable values are .50 or less and statistically significant values are .28 or less; with a 4-point scale, acceptable values are .69 or less and statistically significant values are .44 or less. Values that are acceptable, but not statistically significant, are bolded.Table 3: Scale level CVI (S-CVI/Ave) for elements of the IDUQOL measure and manualIDUQOL Element S-CVI/AveAppropriateness of IDUQOL Life Areas (20 items)a 0.97Clarity of IDUQOL Life Area Names (20 items)b 0.99Clarity of IDUQOL Life Area Descriptions (20 items)b 0.98Clarity of Title and Target Population (2 items)b 0.92Ease of Administration Procedure (4 items)b 1.00Ease of Response Formats (2 items)b 0.83Ease of Scoring Procedure (3 items)b 0.94Helpfulness of Provided Examples (3 items)b 1.00Ease of the Record Form to Use (1 item)b 1.00a b Page 6 of 13(page number not for citation purposes)Ratings were made on a 3-point scale. Ratings were made on a 4-point scale.Note. Ease of Record Form result is the same as the individual level findings; this element is included here for completeness. For S-CVI/Ave, the minimum acceptable value is .90. A scale level ADM Index could not be applied here as it requires scales comprised of essentially parallel items.Health and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46the target population and context of use [47]. The IDU-QOL was developed as a measure of broadly defined sub-jective QoL that incorporates both health and non-healthrelated aspects of IDUs' lives. Administration of the IDU-QOL was designed to be sensitive to the diversity of liter-acy levels, English language skills, attention levels, andcognitive abilities of the target population. An importantstep in test development and validation is the evaluationof content validity. The purpose of the present study wasto examine the content validity of various elements of theIDUQOL measure and manual using SMEs and two com-monly used judgmental methods (i.e., CVI and ADM). TheCVI indicates the proportion of SMEs that endorse an ele-ment as content valid whereas the ADM indicates thedegree of disagreement among SMEs in the responseoption selected. Overall, the results of this study providestrong evidence for the content validity of the elements ofthe IDUQOL measure and manual. Specifically, the I-CVIresults supported the content validity of each of the indi-vidual elements. These elements include the appropriate-ness, name, and description of each of the 20 life areas,clarity of the name of the measure, clarity of the targetpopulation, ease of each step of the administration proce-dure, ease of each response format (i.e., chips and smileyface scale), ease of each step of the scoring procedure,The S-CVI/Ave results also supported the content validityof all of the grouped elements of the IDUQOL measureand manual (e.g., Appropriateness of Life Areas, Ease ofAdministration Procedure), with the exception of Ease ofResponse Formats. Two points are worth noting about theEase of Response Formats case. First, when examined indi-vidually using I-CVI, each of the two items under Ease ofResponse Formats was endorsed by five of the six SMEs,supporting their content validity. In fact, the one SMEwho supposedly did not endorse either of these itemsactually circled both 'somewhat easy to use' and 'mostlyeasy to use' (responses that fell into the 'not endorsed' and'endorsed' categories, respectively) in each case and indi-cated that the ease of each response format for the targetpopulation was an empirical question that should bepiloted instead. Using a conservative approach, we treatedthis SME's response as a non-endorsement, although itcould be argued to be more ambiguous. Second, it shouldbe noted that when there are only two or three items mak-ing up a grouping of elements (as is the case for the two-item Ease of Response Formats grouping), the minimumacceptable level of .90 for S-CVI/Ave cannot be reachedunless all but one item in the grouping achieves endorse-ment by all six of the SMEs. Taking each of these pointsinto account, we would argue that the content validity ofTable 4: Item level CVI (I-CVI) and ADM index values for IDUQOL measure and manual elementsIDUQOL Content Validity Questionnaire Itema I-CVI ADM IndexClarity of Title 0.83 .67Clarity of Intended Population 1.00 .00Administration Procedure – Introduction 1.00 .28Administration Procedure – Respondent Selects Life Areas1.00 .44Administration Procedure – Respondent Rates Importance1.00 .00Administration Procedure – Respondent Rates Satisfaction1.00 .00Response Format – Easy for Respondent to Use Chips0.83 .67Response Format – Easy for Respondent to Use Smiley Faces0.83 .67Scoring Procedure – Relative Importance Score 1.00 .44Scoring Procedure – Importance × Satisfaction Score1.00 .44Scoring Procedure – Obtain Summed Score 0.83 .67Example – Relative Importance Score 1.00 .00Example – Importance × Satisfaction Score 1.00 .00Example – Completed Sample Record Form 1.00 .00Ease of the Record Form to Use 1.00 .28a Ratings were made on a 4-point scale.Note. I-CVI: 1.00 = endorsement by all six subject matter experts (SMEs); 0.83 = endorsement by five of six SMEs. ADM Index: with a 4-point scale, acceptable values are .69 or less and statistically significant values are .44 or less. Values that are acceptable, but not statistically significant, are bolded.Page 7 of 13(page number not for citation purposes)helpfulness of each of the provided example boxes in themanual, and ease of use of the IDUQOL record form.the response formats should not be discounted, but thatcare should be taken to ensure, through further study orHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46pilot testing, that these response formats are appropriateto the group of IDUs with whom a researcher or practi-tioner wishes to use the IDUQOL. Based on interviews weconducted with the experienced staff who administeredthe IDUQOL to participants in another study [44,61], thatsample of IDUs did not have difficulty using eitherresponse format, although some respondents expressedthe desire for a neutral response option on the Likert-typesmiley face satisfaction scale.In terms of the ADM results, practical significance wasobtained for all 75 elements of the IDUQOL and manual,indicating a high level of agreement among the SMEs intheir ratings. However, statistical significance was notreached for the following nine elements: (a) names for theDrugs and Independence & Free Choice life areas, (b)descriptions for the Being Useful, Drugs, and FeelingGood about Yourself life areas, and (c) clarity of title, easeof response format – chips, ease of response format – smi-ley faces, and ease of scoring procedure – summed score.Thus, for these elements, it is possible that SME agreementon the ratings may have occurred by chance alone.Both the CVI and ADM results and the open-ended feed-back from the SMEs were used to make seven main revi-sions to IDUQOL elements. First, the names for the Drugsand Independence & Free Choice life areas were changedto Drugs & Alcohol and Free Choice, respectively. We alsodecided to take one SME's suggestion to change the Edu-cation life area to Education & Training.Second, descriptions for the life areas of Drugs & Alcohol,Education, Family, and Sex were expanded. The originaland revised descriptions for each of these life areas areprovided in Figure 1. The descriptions for some other lifeareas (e.g., Being Useful, Feeling Good about Yourself)remained unchanged because SMEs had only commentedon the visual image used or had not provided any sugges-tions for changes.Third, we added Sense of Future as a life area to the IDU-QOL with the following description: "e.g., hopefulness,aspirations, dreams, goals". The SMEs made several sug-gestions for life areas that could be added to the IDUQOL(i.e., food, pets, personal safety, sense of future, employ-ment, pain). After considerable thought and given previ-ous IDU focus group discussions about important lifeareas, we ultimately decided to only add Sense of Futureas its own life area to the measure. However, we recognizethat other researchers and practitioners may want to con-sider including these suggestions as additional life areas intheir own work. Three points about our decision areworth noting: (a) following discussion, we decided thatdescription of the Health life area, and (c) we resisted add-ing employment as its own life area because IDUs in aconcurrent focus group study strongly opposed viewingemployment as separate from, or more important than,other aspects of 'being useful in society'.Fourth, we made revisions to the visual depictions forFriends, Family, Being Useful, and Free Choice. Based onSMEs' comments, we increased the diversity of people inthe cards for Friends and Family (see Figure 2). For theBeing Useful and Free Choice life areas, SMEs recom-mended using different images to make these conceptsclearer to respondents. The old and new cards are shownin Figure 3.Fifth, we were particularly struck by one SME's suggestionthat the poker chips used in the response format forimportance ratings might act as a trigger for IDUs withgambling issues and so we changed these to unmarkedchips. We also incorporated suggestions made by SMEsfor simplifying the instructions given to IDUs in the man-ual about how to use the chips to indicate the importanceof the different life areas.Sixth, we changed the Likert-type smiley face scale used torate satisfaction from a 6-point scale to a 7-point scale thatwould permit a neutral response. This was based not onlyon SMEs' suggestions but also on our own concurrentexperiences in administering the IDUQOL to IDUs[44,61]. We found that it was particularly appropriate tohave a neutral option available when the respondent wasrating satisfaction with a life area that had not been ratedas particularly important.Seventh, we revised the headings used in the IDUQOLrecord form so they would better match the terms used inthe manual and would make obtaining the summed scoreeasier (see Figure 4.)Given the strong support provided by this study for thecontent validity of the IDUQOL and its manual, the revi-sions made to improve them further, and previousresearch supporting the validity of inferences made fromthe IDUQOL [44,61], the IDUQOL is a viable instrumentfor assessing broad-based QoL in IDUs and potentially innon-injection drug users [45]. The majority of publishedresearch in which QoL is examined with IDUs focuses onHRQOL. Future research is needed that examines theimpact of drug use and various treatment options on QoLusing broadly defined subjective QoL measures such asthe IDUQOL. Future research on the IDUQOL needs tofurther examine its appropriateness and usefulness withnon-injection drug users, its sensitivity to change, and itsPage 8 of 13(page number not for citation purposes)'personal safety' was an implicit part of NeighborhoodSafety, (b) we decided to incorporate 'pain' under ourrelationship with other broad-based QoL measures suchas the Quality of Life Interview – Brief Version, which wasHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46originally developed for use with the mentally ill, or thePersonal Wellbeing Index, which is the successor to theComQol-A5 and was developed for use with the generalpopulation [62].ConclusionThe results from the present study provided strong sup-port for the content validity of the elements of the IDU-QOL measure and manual. Further revisions were madebased on the CVI and ADM results as well as the open-Drugs & Alcohol, and Education & Training), (b) anexpanded description for the Drugs & Alcohol, Education& Training, Family, and Sex life areas, (c) the addition ofSense of Future as a life area, (d) revisions to the visualdepictions for Family, Friends, Being Useful and FreeChoice, (e) the use of unmarked chips rather than pokerchips in the response format for importance ratings, (f)the inclusion of a neutral point on the Likert-type scale ofsmiley faces for rating satisfaction, and (g) revisions to theheadings used in the IDUQOL record form to makeSamples of original and revised IDUQOL card descriptionsFigur  1Samples of original and revised IDUQOL card descriptions.Original card descriptions DRUGS – drug use – e.g., alcohol, heroin, cocaine, crack EDUCATION – e.g., formal schooling, literacy programs FAMILY – e.g., parents, children, siblings, foster families (not friends) SEX – e.g., sexual intimacy, quantity or quality of sex, sex in exchange for money or drugs, sexual abuse Revised card descriptions DRUGS & ALCOHOL – e.g., marijuana, speed, alcohol, heroin, cocaine, crack, etc. and includes selling, buying, and using EDUCATION & TRAINING – e.g., formal schooling, literacy programs, high school equivalency, life skills training, job training, certification, pre-employment programs, language courses (e.g., ESL) FAMILY – e.g., parents, children, siblings, foster families, grandparents, cousins, aunts and uncles (not friends) SEX – e.g., sexual intimacy, sex in exchange for money or drugs, being safe when having sex (use of condoms), birth control, sexual abuse Page 9 of 13(page number not for citation purposes)ended feedback from the SMEs. These revisions included(a) revised names for three life areas (now Free Choice,obtaining the summed score clearer. These revisions to theIDUQOL resulted in an instrument that is even easier forHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46Page 10 of 13(page number not for citation purposes)Original and revised cards to improve diversity of peopleFigure 2Original and revised cards to improve diversity of people.Original cards Revised cardsOriginal and revised cards to improve poor graphics on cardsFigure 3Original and revised cards to improve poor graphics on cards.Original cards Revised cardsHealth and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46researchers, practitioners, and program evaluators to useas a way of assessing and tracking changes in QoL overtime or as a result of interventions in IDUs.List of abbreviationsADM Average Deviation Mean IndexCVI Content Validity IndexIDUs injection drug usersIDUQOL injection drug user quality of life scaleQoL quality of lifeSMEs subject matter expertsCompeting interestsOriginal and revised IDUQOL record form headingsFigure 4Original and revised IDUQOL record form headings.IDUQOL record form   (original) TOTAL NUMBER OF CHIPS USED (TN): _______ LIFE AREA WEIGHTING RATING SCOREBEING USEFUL _____ chips y TN = _______ x ______ = _______ COMMUNITYRESOURCES _____ chips y TN = _______ x ______ = _______ etc. etc. etc. etc. IDUQOL record form   (revised) TOTAL NUMBER OF CHIPS USED (TN): _______ LIFE AREAIMPORTANCERATINGIMPORTANCEWEIGHTINGSATISFACTION RATINGQOLSCOREBEING USEFUL _____ chips y TN = _______ x ______ = _______ COMMUNITYRESOURCES _____ chips y TN = _______ x ______ = _______ etc. etc. etc. etc. Page 11 of 13(page number not for citation purposes)HRQOL health-related quality of life The author(s) declare that they have no competing inter-ests.Health and Quality of Life Outcomes 2007, 5:46 http://www.hqlo.com/content/5/1/46Authors' contributionsAH obtained funding, designed the study, directed the sta-tistical analyses, prepared the initial draft of the manu-script and conducted revisions. AP conceived of the study,obtained funding, coordinated data collection, and con-ducted revisions of the manuscript. Each author read andapproved the final manuscript.AcknowledgementsThis research was supported by an operating grant from the Canadian Insti-tutes of Health Research (CIHR) to Dr. Anita Palepu and Dr. Anita Hubley. Additional support was provided through a Canadian Institutes for Health Research New Investigator Award and a Michael Smith Foundation for Health Research Senior Scholar Award to Dr. Anita Palepu. We thank Dr. Bruno D. Zumbo and Lara Russell for their comments on an earlier draft of this manuscript.References1. Globe DR, Hays RD, Cunningham WE: Associations of clinicalparameters with health-related quality of life in hospitalizedpersons with HIV disease.  AIDS Care 1999, 17:71-86.2. Koch T: Life quality vs the 'quality of life': Assumptions andunderlying prospective quality of life instruments in healthcare planning.  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