In the English language, the word “that” used as a conjunction can illuminate meaning and make for easier comprehension. Yet, today more and more editors and speakers eliminate the word, and clarity suffers. Here are examples from September 4 news accounts, the first from a newspaper business section, the second from a wire service.
VoloMetrix says its algorithms are designed to avoid scooping up non-work-related data, and in reports it defaults to group-related data on employees, not personally identifiable information—Seattle Times
If “that” followed “says” in the first line and followed “and” in the second, the meaning would be clearer.
He confirmed the family had wanted to go to Canada but now only wants to return to Kobane to bury their dead.—Agence France-Presse
The sentence is not technically wrong, but if “that” followed “confirmed”, the reading would be smoother. As it is, the eye stumbles momentarily.
Here is another example, hypothetical but common:
The senator said today his candidacy was in good shape.
“today” could refer to “said” or to his candidacy. If “that’ followed “said” there would be no doubt. It would also make the sentence a bit less awkward.