What reasoning error occurs when an observation about individual members is applied to the entire group?

The reasoning error where an observation about individual members is mistakenly applied to the entire group is known as the composition fallacy. This occurs when generalizations are made from the specific characteristics of individual members to assumptions about the group as a whole without sufficient justification. For example, if one claims that because John is an excellent basketball player, all members of his basketball team must also be excellent players, this would be an instance of the composition fallacy.

In contrast, other errors like hasty generalization involve making broad claims based on insufficient or limited evidence but focus more on the quick assumption rather than the specific characteristics applicable to a group. Non-sequitur relates to statements whose conclusions don't logically follow from the premises, and faulty analogy pertains to comparisons that are improperly drawn between two contrasting entities. The composition fallacy specifically highlights the incorrect leap from specific to general, making it an important distinction in logical reasoning.