Responding to (“Fact checkers must look at truth,” Journal, Nov. 17).

When communicating, it is often helpful to have a shared definition of language and utilize critical thinking skills to clearly evaluate fact from opinion.

The definition of a composite index by the website Investopedia is a “statistical tool that groups together many different equities, securities or indexes in order to create a representation of overall market or sector performance.”

Based on this definition, an example of fact is that the Dow, Nasdaq Composite and S&P 500 are all examples of composite indexes.

Another example of fact is that over the last six-month period (May 24, 2021, to Nov. 24, 2021) all of the composite indexes listed above (and index funds like the TSP C Fund that track them) have increased in value.

The Oxford English dictionary defines opinion as “a view or judgment formed about something, not necessarily based on fact or knowledge.” Opinions often begin with “I think” and include personal experiences, beliefs and emotions, which may distort a individual perspective.

An example of opinion: I think we should use facts in quantitative analysis.

Sean Flaherty

Cortez