A more thorough explanation:

Definition: The certainty effect is a cognitive bias where people tend to spend more time and money looking for information than necessary because they believe it will make a decision certain. This means that information that may only slightly increase the probability of something happening is seen as more important if it can make the outcome certain.

Example: Imagine you are trying to decide whether to invest in a new company. You have done some research and believe there is a 90% chance the company will be successful. However, you keep searching for more information because you want to be absolutely certain. Even if the new information only increases the probability of success from 90% to 95%, you may still spend a lot of time and money trying to find it because you believe it will make the decision certain.

Explanation: The example illustrates the certainty effect because the decision maker is spending more time and resources than necessary to find information that will only slightly increase the probability of success. The decision maker is motivated by the desire to make the decision certain, even though it is already highly likely to be successful. This bias can lead to inefficient use of resources and can prevent people from making decisions in a timely manner.