questionnaire development: an examination of the nordic musculoskeletal questionnaire

Questionnaire development: an examination of the Nordic Musculoskeletal Questionnaire

C E Dickinson, K Campion, A F Foster, S J Newman, A M T O'Rourke and P G Thomas

Technology and Health Sciences Division, Health and Safety Executive, Magdalen House, Trinity Road, Bootie, L20 3QZ, UK

This paper describes the outcome of user trials of the Nordic Musculoskeletal Questionnaire which encompassed the views of the following groups: data entry clerks, technical staff, administrative clerks and 481 subjects employed in 10 supermarkets. A significant number of improvements was identified, especially concerning its wording, layout and administration. This has led to a standardized version being produced for use in studying the prevalence of reported symptoms in many types of occupational groups.

Keywords: Musculoskeletal, questionnaire design

Introduction

Questionnaire development is a surprisingly complex and onerous task. As a rule of thumb, a good questionnaire may be thought of as a tool that is acceptable to all parties handling the form. The most important group to consider is the subjects - the questionnaire must be understandable to them and the layout such that they answer all of the questions. These needs of the subjects can compromise other require- ments which would permit straightforward computer data entry, and the gaining of all the relevant information for a successful analysis, interpretation and report, unless care is taken. One approach to developing a questionnaire is to travel through the flow-diagram shown in Figure 1. This recommends that time is given to defining what needs to be learnt from the questionnaire, the staff and financial resources available (this has an effect on such issues as how the questionnaire will be administered and whether there are funds for it to be type-set) and how the questionnaire is to be utilized - which occupational groups and to whom in that group (sampling frame). Once the definition stage is completed it is timely to consider if a well recognized questionnaire exists that matches these objectives but, if not, to begin constructing a questionnaire and making arrangements for future pilot studies.

A project group in the Nordic Council of Ministers tackled this area when producing the Nordic Musculo- skeletal Questionnaire (NMQ) 1. When questioning the prevalence of such disorders, this distanced itself from using diagnostic labelling, and simply asked for 'ache, pain, discomfort' arising in nine body areas. It was an

approach attractive to the Health and Safety Executive (HSE) who needed a standard methodology for use by many individuals for identifying the number of workers experiencing musculoskeletal symptoms. It was recognized that the NMQ was suitable for application in a wide diversity of workplaces and could accommodate very large numbers of workers in a study very quickly and cheaply, whilst the extent of its application stands as testimony to its acceptability to the workforce.

Planning the questionnaire Define objectives, resources, terminology

I [ S a m p l i n g [

Define population Sample size Sampling frame

I Questionnaire construction

Prologue Question sequence Questions Language Classification Layout Epilogue Question specificity Data hand ling

I Piloting

Distribute to friends Distribute to I0 subjects Distribute to subjects

Interview = Time them, question order, word changes Action : Check analysis routine, data handling,

estimate repeatability, response rate, meaningless questions.

I I Undertake survey [

Figure 1 Questionnaire development strategy

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However, the acceptability of the questionnaire to the research team has not been extensively reported.

A questionnaire typically contains four sections: a prologue, core questions of the study, a series of classification questions and an epilogue 2. It is suggested that the prologue might include a letter describing the purpose of the survey, and instructions on how to complete the questionnaire. The core questions are obviously prepared to meet the survey's objectives and are to be arranged in an order which will seem natural to those faced with completing the questionnaire. The classification questions are those such as sex or age or handedness; that is, those which provide for sub- grouping for the data analysis stage. Finally, the epilogue thanks the subjects for completing the questionnaire and often instructs them what next to do with it.

The purpose of this paper is to describe our experience and the development of the Nordic Musculoskeletal Questionnaire.

Methods A questionnaire was constructed with a prologue

citing HSE's logo, provision for identification numbers (for both subject and occupational group) and a title to establish the topic of interest. A letter was included to describe the purpose of the study and invite subject participation. Assurances of confidentiality were made, and a section included to explain how to complete the questionnaire.

This was followed by two groups of classification type questions, firstly to identify the subject's age and handedness and, secondly, five questions about the individual's job as a record of exposure. This was followed by a picture of the human form with nine body areas shaded and defined (neck, shoulders, upper back, lower back, elbows, wrist/hands, thighs, knees and ankles). This was relevant to a table that requested a 'yes' or 'no' response for each body area to three questions concerning annual prevalence, any disability during the last year (annual disability) and weekly prevalence. Finally, a statement of thanks constituted the epilogue.

The questionnaire was distributed to a succession of specific groups as part of a piloting exercise.

1. Six HSE professional staff (statisticians, doctors and nurses) for discussions on the technical content.

2. Data entry clerks for their view on improving the layout for ease of input.

3. Ten HSE administrative clerks to gain an idea of time needed for its completion and to highlight any questions not readily understood.

4. Check-out staff at 10 supermarkets (total number = 481) were administered the questionnaire in three different ways. Firstly, by HSE staff seeing small groups of cashiers in a designated room at the store and inviting them to complete the questionnaire. Secondly, at three stores, the retailer's training staff invited their check-out staff to complete the questionnaire in a designated room. Finally, at three

stores, the questionnaires were issued to staff who took them away and were asked to return them to centrally positioned box or person, sealed in an envelope. In each of the three approaches a record was taken in each store of the number of cashiers potentially available to complete the questionnaire versus the numbers that actually did so as an indication of response rate.

One week after completing the questionnaire, 44 of the cashiers were asked to complete the questionnaire again in exactly the same manner to produce the repeatability exercise. A further 10% of the cashiers were interviewed using a checklist to ascertain suggestions for improved layout and phrasing of words or questions.

Improvements were introduced along the way by virtue of a multi-disciplinary working group that met periodically to review progress and agree changes.

Pilot study results Question changes

Several questions were modified from those in the NMQ. For instance, year of birth was amended to date of birth and today's date inserted to enable age to be calculated more precisely. Provision was made so that weight and height could be input in either imperial or SI units. In fact, of the 481 cashiers, all entered their weight in stones and pounds and height in feet and inches.

Repeatability exercise Of the 44 cashiers who completed the questionnaire

on two occasions, the number of non-identical answers varied from 7% to 26% for annual prevalence, 0% to 8% for annual disability and 6% to 19% for weekly prevalence.

All variables were judged to be repeatable though precise duplication was not always evident, even in factual type questions. Whilst all cashiers reproduced their original answer for their sex, 7% of the population were undecided about whether they were right- or left- handed. Date of birth was also found to vary for just over 2% of the cashiers.

Meaningless answers 1% of subjects reported trouble in a body area in the

last week but not so in the last year.

Distribution of missing values The majority of missing values were located on the

questions about annual disability and weekly prevalence for the ankles and knees - essentially those questions in the bottom right-hand corner of the page. Observation of people completing the questionnaire suggested that this was due to the subjects working their way through the three columns of questions in a vertical direction. This was to have been expected given that bold vertical lines separated the three questions. When bold horizontal lines were drawn in and tried', at three of the supermarkets this problem of missing values was eliminated, as all individuals were un- consciously steered to work horizontally from left to right across the page (Figure 2). Further, the cashiers

198 Applied Ergonomics

C E DICKINSON, K CAMPION, A F FOSTER, S J NEWMAN, A M T O'ROURKE AND P G THOMAS

Please answer by using the tick boxes [2] - one tick for each question

Please note that this part of the questionnaire should be answered, even if you have never had trouble in any )arts of your body.

Have you at any time during the last 12 months had trouble (such as ache, :)ain, discomfort, numbness) in:

Have you had trouble during the last 7 During the last 12 months have you days: been prevented from carrying out

normal activities (eg. job, housework, hobbies) because of this trouble:

Neck 2 Neck No Yes No Yes

,[-1 21-] ,1-1 2D 4 Shoulders

No Yes

1 D 2 D in the right shoulaer

3 [ ] in the left shoulder

4 D in both shoulders

17 Elbows No Yes

1D 2r - ] in the right elbow

3 D in the left elbow

4 ~ tn both elbows

10 Wrists/hands No Yes

1[ -~ 2 ["'~ in the right wrisVnand

3 [~] in the left wrist/hand

4 ~ in both wrists/hancls

13 Upper back No Yes

'D ,I-]

5 Shoulders No Yes

1 r ] 2 D in the right shoulcler

3 D in the left shoulcler

4 ~ in both shoulders

8 Elbows No Yes

1~1 2D in the right elbow

3 [~] in the left elbow

4 [""] in both elbows

11 Wrists/handSNo Yes

,I-I ,D

,I--1 14 Upper back

No Yes

'D 21-1

in the right wrist/hand

in the left wrist/hand

in both wrists/hands

16 Lower back (small of the back) No Yes

,I-I ,l-1

17 Lower back No Yes

,I-1 ,I-I

19 One or both hips/thighs/buttocks No Yes

,I--] 21-1

20 Hips/thighs/buttocks No Yes

,D 21-1

22 One or both knees No Yes

,I-1 ,D

25 One or both ankles/feet No Yes

tD ,D

23 Knees No Yes

,~ ,[-]

26 Ankles/feet No Yes

t [ ] ,I-1

Figure 2 Musculoskeletal questionnaire

6

19

Neck No Yes

,l-1 ,D Shoulders (both/either)

No Yes

t[-] ,D

Elbows (both/either) No Yes

,1-1 2D

12 Wrists/hands(both/either) No Yes

'D ,D

15 Upperback No Yes

,I-I ,I-I 18 Lower back

No Yes

,I-I ,I-]

121 Hips/thighs/buttocks No Yes

,1-1 ,I-1

24 Knees No Yes

27 Anklee/feet No Yes

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indicated that it was more natural to consider one body area and complete the three questions before moving on to considering their next body area.

Layout interviews Suggestions were made by the cashiers to include an

option for being ambidextrous on the question of handedness. 2% of subjects were found to be ambidextrous.

The wording was amended for annual disability following suggestions from the administrative clerks and cashiers from:

Have you at any time during the last 12 months been prevented from doing your day's work (at home or outside the home) because of the trouble?

Replaced with:

During the last 12 months have you been prevented from carrying out normal activities (eg, job, housework, hobbies) because of this trouble?

The definition of trouble began with "ache, pain or discomfort", this was expanded to "ache, pain, discomfort or numbness" given the outcome of the interviews with some of the cashiers who had severe and prolonged numbness but failed to associate this as being discomfort despite explaining it so to the inter- viewer.

The data entry clerks were generally happy with the layout of questions but particularly emphasized their preference that questions be located in a column to the left, and the answers be positioned in a column over to the right. This meant that they did not have to search across the page for their next input and so were able to enter the data at speed. This was resolved for the classification questions by arranging the questions in a left-hand column and the answer boxes aligned below each other but positioned over to the right leaving a blank column in between. For the questions shown in Figure 2, the order for entering the data was changed so that the clerk worked vertically down each of the three columns. Notating the questionnaires with small-sized input coding (eg, a tick in the 'yes' box was entered as 2), and indications of which computer column numbers this question was assigned, eased both data input and checking.

Very often the preferred order of questions is that judged by subjects as being the most natural order. Subsequently, whereas the Nordic Musculoskeletal Questionnaire asked for Annual Prevalence - Annual Disability - Weekly Prevalence, this was amended to Annual Prevalence - Weekly Prevalence - Annual Disability (as shown in Figure 2).

The use of right justified text in the Nordic Musculo- skeletal Questionnaire was removed given the known difficulties this posed to poor readers unable to handle the uneven amount of spacing between successive words. The use of bold key words was included in places, though care was taken to balance such instances so that several bold words did not cluster together.

The time taken to complete the questionnaire was approximately 4 min though it varied from about 2 to 9 min.

The cashiers claimed to understand all wording being used. Efforts had been made to avoid officious and unfriendly words and included 'you' or 'we' rather than the subject or employee in the introductory letter. All acronyms, abbreviations and technical terms were absent from the draft.

Administrative type The results were very markedly affected by the

response rate arising from the different methods of administering the questionnaire. Figure 3 illustrates this effect for the weekly prevalence of neck trouble in seven of the ten stores visited.

In stores where HSE administered the questionnaire (stores coded 1), all were returned including those on sick leave or annual leave. In stores where the retail staff issued the questionnaires (stores coded 2) the response rate fell slightly. The response rate fell further for those stores where the individuals returned their own questionnaires (stores coded 3) and in the latter, the weekly prevalence of neck trouble was much higher. This suggested that the individuals who returned their questionnaires were, in the main, the one with troubles and a self-interest in doing so.

Discussion

The results demonstrate the value in gaining experience of a questionnaire prior to its inclusion in any major survey. The repeatability exercise was consistent with findings of non-identical answers varying from 0 to 23% reported by Kuorinka et al 1. In their reliability studies, comparisons were made between the NMQ data and information gleaned by a physiotherapist taking a clinical history. When leaving two to three weeks between questioning sessions they concluded that the method of administration had an effect on the repeatability but they did not describe the effect on the prevalence outcome. In this study, the method of administration was demonstrated to be of considerable significance and underlines the need for response rate

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Figure 3 Weekly prevalence of neck trouble in supermarket cashiers

200 Applied Ergonomics

C E DICKINSON, K CAMPION, A F FOSTER, S J NEWMAN, A M T O'ROURKE AND P G THOMAS

figures to be reported in studies of this kind. That the data are vulnerable to such distortion also casts serious limitations on utilizing the reference manuals and data gathered from the Swedish system and reported by Ydreborg and Kraftling 3.

There are benefits attributed to subjects not having to provide their name but this requires detailed arrangements being made in workplaces. Arising from the response rate:prevalence relationship (Figure 3) is the recommendation that future studies necessitate a return exceeding about 80%. Subsequent HSE studies indicate this to be realistic when care is taken.

Whilst this work has been valuable in producing an improved English version of the NMQ, further improvements should be considered in the future. Of particular relevance is the inclusion of questions to indicate which reports of symptoms are believed to be work-related.

The HSE's eventual questionnaire is to become its standardized questionnaire tool for identifying the size of a musculoskeletal problem in workplaces. Large workplaces can be studied very quickly, cheaply and validly by having the questionnaire and computer analysis programs immediately available. Further benefits will accrue from an expanding databank of occupational populations to facilitate comparisons to be made. Its simplicity permits a sizeable number of specialists to use the questionnaire as a means to identifying those workplaces and subjects necessitating a more in-depth

examination. Precise standardization of the method of administration in some workplaces is not always practical, though recommendations are provided to HSE's specialists with the caveat that surveys are not analyzed unless a response rate exceeding 80% is achieved.

References

1. Kuorinka, I, Jonsson, B, Kilbom, A, Vinterberg, H, Biering-Sorenson, F, Anderson, G and Jorgensen, K 'Standardized Nordic Questionnaires for the analysis of musculoskeletal symptoms' Appl Ergonomics Vol 18 No 3 (1987) pp 233-237

2. Wilson, J R, and Corlett, E N (eds) Evaluation of human work. A practical ergonomics methodology Taylor and Francis (1990) pp 71-85

3. Ydreborg, B and Kraftling, A Referensdata Till Formu- laren FHV 001 D, FHV 002 D, FHV 003 D, FHV 004 D och FHV 007 D. Rapport 6 (1987)

Bibl iography

1. Abramson J H Survey methods in community medicine. An introduction to epidemiological and evaluative studies Churchill Livingstone (1984)

2. Andersson, K, Karlehagen, S and Jonnsson, B 'The importance of variations in questionnaire administration' Appl Ergonomics Vol 18 No 3 (1987) pp 229-232

3. Cutts, M and Maher, C Writing plain English: A guide for writers and designers of official forms, leaflets, letters, labels and agreements Plain English Campaign (1980)

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