The term correlation in mass communication refers to the function of

In mass communication the correlation function means interpretation of the raw facts that have been collected.

It selects, evaluates and explains events so that scattered information gains meaning and public opinion can form.

Editorials, commentary and analysis are its typical vehicles, prescribing how audiences might respond to happenings.

The mere gathering of raw data is surveillance, the watch function, and stops before any meaning is added.

Passing culture and social values from one generation to the next is the transmission or socialization role, a separate function.

The idea of investigation is not one of Lasswell's recognised media functions at all and does not describe correlation.