The outcome measures will be measured by questionnaires at baseline and six-months after baseline. Baseline is defined as the start of the intervention, just before the first contact between the ergonomics consultant and the research coordinator in the company.
Process evaluation
The process evaluation of the two guidance strategies will be determined using indicators as defined by Linnan and Steckler [
23] and Murta
et al. [
24]. The following process- and performance indicators will be evaluated: reach, dose delivered, dose received, precision, competence and satisfaction. An additional process indicator is the behavioural change of the construction workers.
Reach is defined as the attendance rate of the construction companies at the intervention. Attendance is defined as the number of construction companies participating in this study relative to the number of construction companies invited through the recruitment strategies. The attendance will be assessed by means of a logbook during the recruitment of the construction companies. Construction companies that will be contacted by the researcher (SV) and do not want to participate will be asked to explain why. Dose delivered refers to the amount or proportion of the intended intervention that is actually delivered to the participating contact persons of the construction companies. Within the six steps of the PE intervention, the dose delivered will be assessed by 31 performance indicators defined by van der Molen
et al. [
12]. Of these 31 performance indicators, 19 are defined as essential. The number of all performance indicators and of the 19 essential performance indicators delivered by the assignments of the ergonomics consultants to the steering committees will be assessed during the face-to-face guidance strategy by means of a logbook filled by an observer who is present at the meetings of the steering committee. For the e-guidance strategy, dose delivered will be assessed by means of the content of the emails from the ergonomics consultant to the contact person. Dose delivered is considered sufficient when at least all 19 essential performance indicators are delivered. When companies drop out of the study or do not follow the entire intervention, reasons why will be asked by the researcher (SV).
In addition, six performance indicators are defined for dose delivered of the steering committee to all construction workers within the included companies. The performance indicators are: 1) received information from the steering committee on the objective of the project, 2) received information on musculoskeletal complaints within the occupation, 3) received information on ergonomic measures, 4) involved with the choice of an ergonomic measure, 5) received information and training of the chosen ergonomic measure, and 6) tested the ergonomic measure in daily work. Dose delivered to the construction workers will be assessed by acquiring all information sent from the steering committee to the construction workers and via attendance lists during the meetings of the steering committee.
Dose received refers to the proportion of activities in the intervention that is actually performed by the steering committees of the construction companies. The performance indicators will be assessed by an observer by means of a logbook during the meetings of the steering committee during the face-to-face guidance strategy. For the e-guidance strategy, dose received will be assessed by means of a logbook by an observer who is present at the meetings of the steering committee and by means of the feedback of the assignments of the steering committees to the ergonomics consultant. Dose received is defined as sufficient when at least the 19 essential performance indicators are performed by the steering committee. Whether the dose is received by construction workers was assessed by seven questions about the seven performance indicators within the questionnaire after six months. In addition to the six performance indicators described above, an extra performance indicator is added to assess whether construction workers had read the delivered information. Dose received is sufficient when all seven performance indicators are received.
The precision of the intervention is defined as whether construction companies implement ergonomic measures described by the websites of Arbouw or codes of practice. If the implemented ergonomic measures are described by these websites or catalogues, the required precision is considered to have been reached.
The question of whether the ergonomics consultant has the competence to guide the steering committees of the construction companies will be asked with the help of a questionnaire after the six months of guidance has been completed. The contact person will be asked whether the assignments in preparation of the meetings were clear, whether the objectives of the four meetings were clear, whether the objectives of the feedback of the assignments to the ergonomics consultant were clear, whether the questions asked by the contact person were answered satisfactorily, and whether the ergonomics consultant was able to help with problems occurring during the six months of guidance. All items will be answered with yes or no and additional information on the given answer will be requested.
After six months, the company stakeholders within the steering committee are asked via a questionnaire whether they were satisfied with the guidance strategy and if it had been of value for the construction company. The questionnaire contains seven items, including the duration of the intervention, the duration of the meetings, the involvement of construction workers with the choice of an ergonomic measure. In addition, with two open-ended questions, members of the steering committee can give suggestions for improvements to the intervention, to the guidance strategy, and to the consultant. With the exception of the duration of the intervention and the open-ended questions, all items will be answered with yes or no. For all questions, additional information on the given answer will be requested.
The behavioural change of the construction workers consists of six topics: knowledge, attitude, motivation, ability to use, facilitation and culture. It is considered that the interventions will change the behaviour of construction workers towards working with ergonomic measures. Therefore, measurements of the items for behavioural change will be done at baseline and after six months by means of a self-made questionnaire.
First of all, the knowledge of the relationship between ergonomic measures, physical work demands and musculoskeletal disorders will be asked through two statements. An example of a statement is: “Due to long and frequent lifting and bending, I have an increased risk of low back pain. This can be reduced by using a raised hod”. The statements will be adapted for the different occupations, and construction workers will be asked if they agree with the statement. They can answer with a ‘yes’ , ‘no’ or ‘I don’t know’. Knowledge will be rated as good when both questions are answered affirmatively, and knowledge within a construction company is defined as good when the knowledge of 75% of all the construction workers within the company is rated as good.
The attitude of the construction workers towards working with ergonomic measures is asked with five yes or no items, such as “I only use ergonomic measures when I have physical complaints”, and is defined as good when four of the five items are scored positively. On the company level, attitude is considered good when at least 75% of the construction workers scored positively.
The motivation to work with ergonomic measures is asked through a single yes or no question. This question is: “When your employer provides ergonomic measures, are you willing to use them?” If the question is answered in the affirmative, construction workers are considered to have the motivation to work with ergonomic measures. Motivation is considered as good at company level when at least 75% of the construction workers answered the question in the affirmative.
Of the four earlier defined clusters of ergonomic measures, the ability to use these ergonomic measures will be asked. For each cluster, construction workers can assess their ability as good or poor.
As with the ability to use, the facilitation of each of four clusters of ergonomic measures will be assessed. In addition, a question is asked concerning whether the construction company has set up rules or procedures for the use of ergonomic measures.
The final topic of behavioural change is the culture of the construction company. By means of three items, the values and expectations of construction companies towards working with ergonomic measures will be asked. An example of such an item is: “It is expected of me and my colleagues that we work with ergonomic measures as much as possible”. The culture of the construction company is positive for an individual construction worker when all three items are answered affirmatively. At least 75% of the construction workers must experience a positive culture for the construction company to be considered as possessing a positive culture.
Economic evaluation
A cost-benefit analysis for each participating construction company will be made. At baseline, demographic characteristics of the employees with respect to sick leave will be assessed for the construction companies. The costs of the intervention will be assessed at the end of the intervention by multiplying the time spent by the ergonomics consultant with the hourly costs. In addition, at the end of the intervention, the director of the construction companies will be asked about the costs regarding employing the ergonomic measures and additional energy and the maintenance costs of the ergonomic measures. Furthermore, the director is asked if the production per working hour changed by using the ergonomic measure.
On the benefit side, construction workers will be asked at the end of the intervention how many days they could and did use the ergonomic measure during the previous 10 working days. In addition, construction workers are asked how they judge their physical work demands compared to working without the ergonomic measure. These three questions will provide a benefit for reducing risk factors for work-related musculoskeletal disorders. Another benefit aspect will be the change in production per working hour and change in quality of the work.
With the help of the Dutch Economic Institute of the Construction Sector, the above-mentioned aspects on the company level and on the individual worker level will result in a cost-benefit analysis for each construction company.