Decline effect

The decline effect is when an experiment isn't able to produce the same results over and over again. It can happen in many different areas of science and happens when something that was previously thought to be true stops working and the results keep getting less reliable over time. For example, if you have a medicine that works really well for a certain illness, it might work really well at first but then over time, it might become less effective, leading to a decline in the results and effectiveness.