Is organizational intervention using Layered Voice Analysis (LVA) effective in addressing operator mental health in call centers?

INTERVENTION: The participatory approach group by LVA. (Baseline‐12weeks) Line care from supervisor using LVA. (Baseline‐12weeks) Normal line care from supervisor. (Baseline‐12weeks) Active control. (Baseline‐12weeks) CONDITION: Mental health PRIMARY OUTCOME: CES‐D (The Center for Epidemiologic Studies Depression Scale) SECONDARY OUTCOME: UWES (Utrecht Work Engagement Scale), WHO‐HPQ (Health and work Performance Questionnaire), PSQI (pittsburgh sleep quality index), Unidentified complaint (eg., headache, neck pain, dizzy, low back pain), Work motivation and performance (eg., Call Per Hour, Average Handing Time) INCLUSION CRITERIA: