## 2 Materials and Methods
### Research Tools
#### 2.3.4 Module A--Intervention Group  
The intervention group received a training module (Module A) constructed using a targeted approach, taking into account the participants' sociodemographic characteristics and questionnaire responses. The different aspects of the module are described below:  
1. Settings and duration The training session was conducted in a classroom setting, accommodating thirty workers at a time. A presenter delivered the module in the form of presentation slides. The session lasted one hour.
2. Language and complexity of content Most of the participants only received formal education up to secondary school. Hence, the module content was written in plain and straightforward Malay, minimising unnecessary technical terms. The participants were briefed on the following topics: sound and noise, the hearing system, health effects of noise, hearing conservation programme, and noise hazard control. Diagrams and analogies were used to explain relevant concepts. None of the participants were in managerial or administrative positions. Rather, they were all stationed along the mill's production line and were constantly exposed to excessive noise during working hours. Hence, when explaining noise-hazard control, we focused on the appropriate actions at the personal level (wearing HPD) instead of elaborating on engineering and administrative control measures.
3. Emphasis on relevant points The participants' questionnaire responses provided insight into the factors that affected their use of HPD. The main barriers to compliance were the lack of comfort and difficulties in communicating when wearing the devices. While most of them agreed that they were susceptible to hearing loss due to their working environment, 1 in 6 participants was unaware of the irreversibility of noise-induced hearing loss. Interpersonal and situational influences did not hinder their use of HPD. Based on these responses, we fine-tuned the module content to emphasise the hazardous effects of noise on workers' health, notably the permanent nature of noise-induced hearing loss, and hence the need to use HPD at all times when working in noisy environments. We also stressed the importance of preserving any remaining hearing capability for those who had already developed hearing loss.
4. Noise map The mill conducts yearly noise-risk assessments as part of its hearing-conservation programme. We obtained the noise map of the mill from the latest  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Domain** & **Number of Items** & **Mean** & **SD** & **Cronbach’s Alpha** \\ \hline Benefit of HPD use & 5 & 3.31 & 0.4 & 0.9 \\ Barriers to HPD use & 10 & 2.18 & 0.41 & 0.84 \\ Self-efficacy in HPD use & 5 & 2.7 & 0.44 & 0.79 \\ Susceptibility to hearing loss & 2 & 3.12 & 0.5 & 0.86 \\ Severity of hearing loss & 6 & 3.25 & 0.61 & 0.78 \\ Interpersonal influences & 3 & 3.04 & 0.41 & 0.74 \\ Situational influences & 5 & 3.38 & 0.42 & 0.91 \\ \hline \end{tabular}
\end{table}
Table 1: Summary statistics and internal consistency measures of the predictors of HPD use.  
noise-risk assessment report and presented it in one of the slides to improve the workers' understanding of the noise hazard present at their workstations.
* Audiogram readings Participants were handed a copy of their latest audiometric test results during the session. As the presenter explained the audiogram interpretations, the participants could compare their audiograms with the examples shown on the slides. This method made the session more interactive for the participants.
* Technique demonstration The final part of the training session included a demonstration of the correct technique for wearing HPD.