Poor performance leads to work not getting done on time and poor quality. When products and services are not done correctly, they need to be done over. Repeating any process costs money. Workplace injuries cost companies a lot of money in prevention programs, worker's compensation, and replacement workers. All of these factors lead to higher turnover.
High turnover leads to money being spent on training new employees.
Discuss alcohol and illegal drug use. Use of alcohol or illegal drugs while working is definitely related to poor performance and accidents. Long-term abuse of alcohol or illegal drugs is linked to health problems such as heart disease, cancer, and liver disease. Even occasional partying the night before work can impact a person's job. Calling in sick and poor job performance when at work can affect a person's job evaluations and opportunities to advance in the company.