Which of the following is NOT listed as a method to improve reliability?

Improving reliability in operations management focuses on ensuring that systems and components perform consistently over time without failure. The methods that are commonly employed to enhance reliability typically include component design, which involves designing parts to withstand use over time; production and assembly techniques that ensure quality and reduce the potential for defects during the creation of products; and preventive maintenance procedures that involve regularly scheduled checks and upkeep to prevent equipment failures.

Increasing environmental stressors, on the other hand, would likely have the opposite effect on reliability. Introducing more stress or demanding conditions to a system could lead to a higher risk of failure, thus undermining reliability. This method does not align with the goal of maintaining or improving the consistent performance of a system and is not considered a viable method for enhancing reliability. Therefore, it stands out as the correct answer for something that is NOT typically used to improve reliability.