Final answer:
Controls lose effectiveness due to a lack of resources and monitoring, overconfidence or complacency, equipment limitations, and disruptive external factors. Ensuring longevity requires balancing practical execution with scientific rigor.
Step-by-step explanation:
There are several factors that can cause controls that are established and implemented for a prolonged period to lose their effectiveness. One such factor is lack of resources and monitoring, which could include issues such as excessive paperwork, insufficient supplies, or insufficient feedback, leading to an inability to conduct long-term follow-up evaluations effectively. Another is overconfidence or complacency among staff, which can stem from a disconnect between scientific ideals and practical realities, reducing the rigidity needed for consistent execution of control measures. Equipment serviceability and availability also play a crucial role; limitations in measuring devices or a lack of skilled personnel can introduce uncertainty into the system. Lastly, external factors such as unrelenting hostile encounters can disrupt control measures, especially when there's an unexpected loss of a critical resource without adequate preparation. Balancing scientific rigor with sustainability and practicality is essential in ensuring the continued efficacy of these controls.